What does all this tech jargon mean? Firmware? Multi-touch? UDID? Why can't technology companies use normal English?

Terrified of tech terminology? Baffled by buzzwords and jaded by jargon? You're not the only one. Welcome to the Apple user's jargon-buster dictionary.

The simple fact is that technology companies can't always use normal English because they deal in so many new concepts - concepts that are often newer than the most recent edition of your favourite dictionary. Luckily you've got access to Macworld.co.uk, which is updated a lot more frequently.

In our tech glossary, we explain all the technology jargon that we think an Apple fan is likely to encounter. A lot of the terms here are therefore specific to Apple products or services (Retina displays, Time Machine, Objective C, Xcode), but we've included plenty of broader terms too, when we think they are ones that will affect owners of iPhones, iPads and Macs.

Periodically we'll update this article to explain more Apple-related technology terms in plain English. Let us know in the comments if there are any confusing words or acronyms you want us to explain.

Updated, 19 October 2015

See also: Macworld's complete Apple A - Z - your total guide to the Cupertino-based company

Quick jump:

What is 802.11 (a, b, g, n, ac)?

These are different types of Wi-Fi (or AirPort) technologies. IEEE 802.11, to give the technology its technical title, is a set of wireless specifications created by the Institute of Electrical and Electronics Engineers. They create a set of wireless specifications and companies like Apple follow them to ensure that devices (such as the iPhone) can talk to other devices (such as Internet Routers).

The various different flavours of 802.11 Wi-Fi have different speeds, power requirements and so on. 802.11ac is the most recent to be ratified and offers an estimated multi-station WLAN throughput of upwards of 1 gigabit per second; 802.11ac is covered by Apple's most recent AirPort Extreme wireless router.

Read next: Apple Wi-Fi router buying guide: Which AirPort is right for you?

What is a 3D printer?

A futuristic type of printer that builds 3D objects, typically made from plastic. These can be virtually any shape, and it is possible to download 3D designs and build the object at home.

Some controversial objects have been created using 3D printers, including guns.

Stratasys Objet500 3d printer

What is 3D Touch?

A new touchscreen technology announced by Apple at the launch of the iPhone 6s and 6s Plus. The screens of those two phones are sensitive to varying degrees of pressure, which means you can activate distinct functions and commands depending on how hard you press.

Read more: 11 great 3D Touch tips & tricks for iPhone 6s and 6s Plus

What is 3G?

This is a network technology used to to deliver internet data over the mobile phone network. You need to sign up for Internet Data with your mobile phone company to access 3G or 4G networks. Also known as Mobile Broadband.

What is 4G (LTE)?

4G and LTE (Long Term Evolution) are newer types of mobile internet. They offer faster speeds and greater reliability than the 3G network.

While 4G will eventually replace 3G, for now both networks run side by side, and your average iPhone can access both 3G and 4G (as well as lesser known standards such as Edge). Most mobile phone providers are now offering 4G along with 3G as standard, for either the same price or a slight increase.

Carphone Warehouse (which admittedly has a vested interest in bigging up the technology) says 4G coverage is accessible to 80 percent of the UK population at present, and claims this number will rise to 98 per cent in the next year.

See also: Should I get 4G for my iPhone and iPad?

What is 4K?

A new type of television and monitor that is hoping to replace high-definition. 4K stands for 4,000, and is so named because it will have around 4,000 horizontal pixels. This compares to the 2,560 x 1,440 found on a current 27-inch iMac. Although actual resolutions still vary, the most common is 3840x2160 pixels, which is four times larger than a high definition television set.

Editing 4K video is very demanding on a computer, and the Mac Pro is designed to be capable of 4K video editing.

(Incidentally, one of the rumours about the iPad Pro suggests that it will have a 4K screen, which would be very impressive indeed.)

Tech jargon buster: A

Simon Jary's A to Z of Apple: Apple's A1 Aqua alphabet

What is an accelerometer?

This is a motion detector sensor that Apple first introduced in the iPhone. It is now found in the iPhone, iPod touch and iPad. It is the sensor that detects which way up you are holding the device, so the screen can rotate accordingly. Some games (and other apps) use the accelerometer as an input control (twisting the iPhone to recreate the movement of a steering wheel, for example)

What is accessibility?

Accessibility (in a technology context) is a general term for features offered by devices and operating systems to make them easier to use for people with visual or physical impairments.

iOS changes we'd like to see: Accessibility

What is Address Book?

Mac OS X program used for storing the names and addresses of people you know. The equivalent program is called Contacts on iOS devices.

See: 5 fantastic Address Book secrets

What is Airplane Mode?

A simple feature of iOS that switches off all cellular, wireless and Bluetooth activity on an iPhone or iPad. You won't be able to pick up emails or tweets, access Game Center or (obviously) browse the internet. Can be switched on via the Settings app or, in iOS 7 or iOS 8, from the Control Centre.

It's designed to make smartphones and tablets safe for use on a plane, but in our experience you'll probably still be asked to switch off the device completely for take-off and landing.

What is Android?

A mobile phone operating system platform created by Google. Android and iOS (the iPhone and iPad system) are the two largest mobile operating systems in the world.

Android differs from iOS in that it's a partly open-source system: Google releases the source code and allows product manufacturers to adapt the original code to create custom operating systems for their devices. Amazon famously did this with its Kindle device, replacing many Google services with its own.

See also: iPhone vs Android: Why the iPhone and iOS beat Google Android

What is an app?

Short for application: the name that Apple gives to programs you install on iOS and Mac OS X devices. (However, there are such things as pre-installed apps, and on non-jailbroken iOS devices you won't be able to delete these.) 

What is an Apple ID?

An account used to make purchases from the Apple Store. Also used to access other apple services like iCloud and Find My iPhone. Can be set up from Settings > iCloud in iOS and Settings > iCloud in Mac OS X.

How to create an Apple ID | How to delete an Apple ID

What is Apple Maps?

A replacement for Google Maps first launched in iOS, and integrated with Mac OS X in Mavericks. Controversial because some people claimed Google Maps was a better service. Okay, pretty much everyone claimed Google Maps was a better service, and remains a better service. It's improving, though, and at least it gets public-transport directions (which Google Maps had before Apple Maps launched) in iOS 9.

Apple Maps vs Google Maps comparison review

What is Apple Pay?

Apple's mobile payment system, based on the Touch ID fingerprint scanner and NFC wireless antennae built into the iPhone 6 and iPhone 6 Plus (although the iPad Air 2 and iPad mini 3 can also use a more basic version of Apple Pay). Launched initially in the US only, but has since come to the UK.

Complete guide to Apple Pay

What is Apple Script?

Easy-to-learn Mac OS X programming language created by Apple to automate programs.

Apple in AppleScript storm

What is the App Store?

This refers to the digital stores where Apple sells apps for iOS and Mac OS X (the iOS store is usually just called the App Store, whereas the Mac equivalent is called the Mac App Store). It also refers to the Apple programs on each of those platforms that allow you to access the stores, and buy, pay for and download the apps. 

What is Arrangement Mode?

Mode that enables you to rearrange the icons on an iOS home screen or within Dashboard in Mac OS X. Identified by the 'jiggling' around of icons and small crosses appearing at their top-left corners. Accessed by holding down any individual app icon for a second or two. Quit Arrangement Mode by pressing the Home button.

iOS Arrangement Mode jiggling icons

Tech jargon buster: B

Simon Jary's A to Z of Apple: Apple's brilliant buzzy Bs

What is Bluetooth?

Technology used to wirelessly transmit data between devices. Principally used to attach accessories (keyboard and mouse) to Mac OS X and iOS devices. Also used to transmit music to compatible speakers. Named, incidentally, after a viking king (a vi-king?), as you can discover in our roundup of tech term origins.

What is Bluetooth 4.0?

The latest full-number version of Bluetooth, a specification with which the iPhone 4S and later are compatible. (Bluetooth 4.1 and Bluetooth 4.2 were launched in December 2014, but the iPhone 6 series came out before then.)

Bluetooth 4.0, also known as Bluetooth Smart, incorporates a low-power standard, which means it can be turned on and left on without causing a drain on the battery. This has enabled services like AirDrop to be possible. Bluetooth 4.0 still drains the battery when connected to a Bluetooth device like an Apple wireless keyboard.

Tech jargon buster: C

Simon Jary's A to Z of Apple: Apple's crazy, crappy Cs

What is CarPlay?

CarPlay is an integrated display system - proprietary to Apple - provided as an optional extra when you buy a new car. A large display sits on the dashboard of your car; you plug your iPhone into the CarPlay system, and use a mixture of Siri voice commands and touch-screen controls to interact with CarPlay.

Apple CarPlay serves up Apple Maps, makes Phone calls, displays Messages, and plays Music.

Read more: What does Apple's new CarPlay system mean for the auto industry?

What are Cloud Services?

Cloud services store information on a remote computer, known as a Cloud Server. An intenret connected device, like an iPhone or Mac, can then access the information as its required. Cloud Servers can also help devices along with computational tasks. Apple’s own cloud service is called iCloud.  

What is Contacts?

The iOS version of Address Book. Used to store details (phone numbers, email addresses and so on) of people you know. You can block a contact from calling you.

What is Control Centre?

New feature in iOS 7 (and continued in iOS 8) that enables quick access to many frequently used settings and features, including the volume and brightness controls, the toggles to switch Airplane Mode, Do Not Disturb mode (which has its own entry below) and Bluetooth on and off, AirDrop, the camera and (on the iPhone) the torch. Accessed by sliding a finger up from the bottom of the screen.

Pleasingly, it is indeed spelled 'centre' rather than 'center', at least on iOS devices in this country. Control Centre is one of the features we discuss in our video '7 things we love about iOS 7'.

iOS 7 Control Centre iPad

What is Crystalwell?

The name for a part of a superior subset of Haswell chips used in certain models of MacBook. 'Crystalwell' is literally the codename of the L4 cache (eDRAM) featured in the Iris Pro-enabled Haswell CPUs.

Read more: What is 'Crystalwell'? We explain an important feature of the new MacBook Pro laptops

Tech jargon buster: D

Simon Jary's A to Z of Apple: Apple's dog-tagged Ds

What is Dashboard?

Feature in Mac OS X that displays icons for programs installed on the Mac OS X computer (similar in style to the Home Screen on iOS devices).

What is DFU mode? (What does DFU mode stand for?)

DFU stands for Device Firmware Update. It's a special mode you can put your iPhone in when you want to a) recover an ailing device, b) install an obsolete version of iOS, c) update your firmware or d) jailbreak. It differs from Recovery Mode in that Recovery Mode forciblt installs the latest version of iOS; DFU mode lets you keep things as they are.

Read more: How to put an iPhone into DFU mode

What is DisplayPort?

A high performance digital interface used primarily to connect a laptop or computer to a display (monitor). It can include both audio and vidoe, and also supports other forms of data like USB. Most Macs use the same interface as Lightning to run Displayport.

What is the Dock?

Feature at bottom of iOS and Mac OS X home screen/desktop that contains icons for commonly used apps. On Mac OS X can also contain folders and documents and the Trash Can. 

What is Do Not Disturb mode?

Mode on iOS devices that blocks phone calls and makes the phone run on silent. Useful for meetings, public events and bedtime.

On default settings, repeated calls to the iPhone will be let through after three rings, but you can tweak the way it works. You can even set it to allow through VIP callers only.

Tech jargon buster: E

Simon Jary's A to Z of Apple: Not all Es are good, Apple

What is an ebook?

An electronic book. Made popular by the Amazon Kindle device and also purchased on iOS devices using iBooks. These are books that can be read on digital devices.

Read next: How to make money selling books on the iBookstore

Tech jargon buster: F

Simon Jary's A to Z of Apple: I know F-all about Apple

What is FaceTime?

Video conferencing technology implemented into iOS and Mac OS X technology. Enables users to easily start video conversations with other FaceTime users.

What is a fanboy?

Disparaging term used, often, by other fanboys who subscribe to a different type of fandom.

Google Android supporters may call users of Apple products fanboys (or fangirls which apparently is worse), thereby accusing them of slavish devotion and unthinking, cultish defensiveness. In the reverse situation the variant 'fandroid' might be used instead. Also heard frequently when discussing rival gaming platforms.

We gathered a few of the more entertaining or aggressive flame comments we've had from Android fanboys (many of them accusing us of being Apple fanboys) in our article Best (and worst) of the Android fanboys: Our 20 favourite troll comments.

What is firmware?

Firmware is program code stored within hardware that determines how it works. Unlike hardware, which is fixed, firmware can be updated (like software). However, firmware updates are infrequent. Firmware updates to Apple hardware are typically handled by Software Update.

What is Find My iPad/Find My iPhone?

App for iOS devices and iCloud web-based service that enables users to locate iOS and Mac OS X devices (iPhones and Macs, and so on). Integrates with Apple Maps and enables users to lock and send messages to missing devices.

What is flame? (And what is flame-bait?)

Flame and flaming are internet terms that refer to abusive (and usually profanity-laden) comments, most commonly posted anonymously on social forums and gaming chat rooms, but also in the comments section of news and comment articles. Journalists whose work is published online quickly develop a thick skin, or learn not to read the comments below their articles.

Ironically, an article that attracts a lot of flame may be considered a success in pure web traffic terms, as the flaming process gains momentum and other users are attracted to the spectacle. This may lead to other commenters accusing the writer of creating the piece as 'flame-bait' - that is to say, a deliberately 'bad' or controversial article designed intentionally to stir up argument and attract trolls or abusive commenters.

What is a flick?

A gesture used in iOS. Made by moving the finger swiftly in any direction (usually up or down). Often used to quickly move up and down a web page or through a long list of items.

Tech jargon buster: G

Simon Jary's A to Z of Apple: Reaching Apple's G spot

What are gestures?

A set of finger movements that you use to interact with touch screen devices like the iPhone and iPad. Common gestures include 'flick', mentioned above; pinch or 'unpinch' (opposite gestures performed with a finger and thumb), and tap.

What is a GPS?

A sensor found inside the iPhone and iPad that helps it determine its position. Used principally in Maps to locate your position on earth. GPS stands for Global Positioning System and works by linking to a network of 24 satellites in orbit around the earth. Apple combines GPS along with triangulation of known Wi-Fi hotspots and mobile phone towers to determine your position. Collectively it refers to these as Location Services.  

Tech jargon buster: H

Simon Jary's A to Z of Apple: Apple's explosive H Bomb

What are haptics? What is haptic feedback?

Haptics are a raft of technologies based around the concept of touch-based feedback: screens that respond to the fingertip in such a way that it feels like you are touching the physical object depicted on them, or like the screen is 'tapping' you to get your attention. By adding a sense of feel, the device tells the user when certain on-screen items have been touched or activated.

Many mobile phones use haptic feedback through subtle use of the vibrating alert. It's perennially rumoured that the iPhone 7 and iPad Air 3, for instance, could have haptic-capable screens, and the iPhone 6s and 6s Plus both incorporate elements of haptic (or taptic) feedback to let you know when you've done a harder press to activate the new 3D Touch features.

Haptics are most well known to Apple fans, however, through their presence on the Apple Watch. See Taptic, haptics, and the body fantastic: The real Apple Watch revolution

Apple Watch

What is Health?

The health-related app that Apple added to iOS 8. It looks after general health information and links to various fitness and monitoring apps and devices.

Here is Apple's description of Health, and here is our guide: Complete guide to Apple's Health and HealthKit.

What is High Definition? (What does HD stand for?)

A video format with a greater resolution than standard definition. Typically more than 720 horizontal lines, although often more than 1080 lines. The three main formats are 720p, 1080i and 1080p. The i stands for Interlaced which blends frames together, whereas the P stands for Progressive which shows one complete frame then the next. P is generally considered better for film and i for fast-moving television.

What is a Home button?

The button on the front of an iPhone, iPod touch or iPad, below the screen. Used to access the home screen. Also used to unlock an iPhone 5s, iPhone 6 or iPhone 6 Plus using Touch ID.

(Pre-Touch ID Home buttons are known to stop working, unfortunately. If your iPhone's Home button isn't responding, try this fix.)

What is a home screen?

The main screen that displays available apps and folders in iOS. You can flick left and right to show more apps and folders.

What is HomeKit?

HomeKit is a developer framework by Apple - a software platform around which other companies will create a variety of home-automation products that can be controlled via iOS devices.

More here: What is HomeKit? We examine Apple's plans to automate your home via your iPhone

What's a hotspot?

A Wi-Fi hotspot is a point where you can access the internet wirelessly; you might find hotspots in various public locations, such as cafés and libraries. You can also create your own Wi-Fi hotspot using your iPhone.

Also worth mentioning what a hotspot is not.

What is HTTPS?

HTTPS, or Hypertext Transfer Protocol Secure, is a secure version of the standard HTTP technology used to deliver page information across the web. An encrypted protocol called SSL/TLS ensures that transmissions cannot be intercepted or altered by third parties.

In other words, look out for 'HTTPS' in the URL of a site you're visiting: it indicates a broadly higher level of security, and offers some reassurance that you're on a legitimate website rather than a data-harvesting imposter.

Tech jargon buster: I

Simon Jary's A to Z of Apple: Apple's eye for an 'i'

What is iBooks?

App created by Apple to display e-books. See: iBooks 3 review.

What is the iBookStore?

Apple store used to access free and purchased iBooks. Part of the iBooks app in iOS, or can be accessed through iTunes on Mac OS X.

What is an ICCID, and what does ICCID stand for?

ICCID is the technical name for what's commonly called a SIM number. It stands for Integrated Circuit Card Identifier. You can read it straight off the SIM card, or access it via your iPhone's Settings app.

Read next: How to find the SIM number (ICCID) on your iPhone

What is iCloud?

A range of cloud services offered by Apple. Notable features include push email, contact sync, calendar sync, Find My iPhone/iPad and iTunes Match.

See also: How to set up iCloud

What is an IMEI, and what does IMEI stand for?

IMEI stands for International Mobile [Station] Equipment Identity. Each mobile phone has a unique IMEI identifier, used for the purposes of listing stolen phones and various other things.

It's easy to find out your iPhone's IMEI: How to find your iPhone's IMEI number

What is iMessage?

Service offered by Apple that enables users to send SMS-style text messages between Mac OS X and iOS devices. Free to send but requires both users to have an Apple ID. If iMessage is not available message is sent from iPhone using SMS instead (which is charged for).

What is the Internet of Things?

The Internet of Things (or IoT) is the currently fashionable term for web- or app-connected devices and appliances outside the traditional realm of tech: cooking appliances, central heating and so on. We look at this in more detail in our article What is the Internet of Things? The best devices to connect to the iPad and iPhone.

What is iOS?

The operating system software used on the iPhone, iPod touch and iPad. The most recent full-number version is iOS 9, which was unveiled at WWDC 2015 in June 2015 and launched alongside new iPhones at a special press event on 9 September.

Read more: What is iOS, should I update iOS, how to downgrade to an earlier version of iOS and more

What is an iPad?

Tablet computer made by Apple. Similar to the iPhone but with a larger display. As of 19 October 2015, four models are available: iPad Air 1iPad Air 2; iPad mini 2 and iPad mini 4. The first two have 9.7in screens, while the smaller minis have a 7.9in screen.

Apple has also announced a fifth, larger iPad, the iPad Pro, which will launch in November 2015.

Read next: iPad buying guide 2015

iPad Air 2

What is an iPhone?

A mobile phone and portable data connected computer made by Apple. There have been 10 models released, with various configurations of each: different storage capacities, cellular connectivity and colours.

Current models available: iPhone 5s; iPhone 6; iPhone 6 Plus; iPhone 6s; iPhone 6s Plus.

We expect more iPhones to launch in September 2016, just as Apple does every September. There will presumably be an iPhone 7 and quite possibly an iPhone 7 Plus; don't bet against an iPhone 6c or some other 4-inch iPhone.

Read next: iPhone buying guide 2015

What is an iPod?

A music player made by Apple: one of the most successful product lines in its history (or in the history of any tech company), although one that's now well on the decline. Not too long ago Apple removed the iPod section heading from its website.

The most modern incarnation is called iPod touch and is essentially an iPhone without the mobile data connection. But Apple still sells more music-focused iPods: the tiny iPod shuffle and the small iPod nano. The relatively big iPod classic was discontinued a little while ago, causing a certain amount of grieving: A Tribute (and Goodbye) to Apple's iPod Classic

What is IPS?

A type of LCD monitor that offers better colour reproduction. IPS stands for in-plane switching and it is widely considered superior to TN (twisted nematic) monitors. Apple MacBooks, iPads, iPhone and iPod touch models all use IPS displays. 

What is iTunes?

Media player/management software made by Apple. Originally designed to play and sync music with the iPod, but the modern incarnation carries out a wide range of duties, from playing music, video and TV shows to storing iBooks, podcasts and apps, and managing iOS devices.

What is iTunes Match?

iCloud Music service offered by Apple that enable users to sync and stream music from multiple iTunes accounts. Free version works with music purchased from iTunes Store, but a paid-for £21.99 per year service works with all your music.

See: Guide to iTunes Match

What is the iTunes Store?

Digital store used to purchase music, movies and television shows. Accessed through iTunes app.

What is iTunes University? (What does iTunes U stand for?)

Part of iTunes Store that enables you to download free video and audio lectures from the world's leading universities. We explain the benefits and features of iTunes U in a separate article: Everything you need to know about iTunes U, and how to get the most out of it.

Tech jargon buster: J

Simon Jary's A to Z of Apple: Apple, now glad to be J

What is jailbreaking?

When you jailbreak an iPhone or iPad, you remove the locks and restrictions Apple puts into place so that you can only install officially approved apps from the Apple App Store. A jailbroken can run non-approved apps, most likely from the Cydia marketplace.

There are risks and drawbacks to jailbreaking, but it's relatively easy and many users swear by it. If you're interested, check out our tutorial: How to jailbreak an iPhone or iPad.

Tech jargon buster: L

Simon Jary's A to Z of Apple: Apple: to L and back

What is a Lightning connector, port, cable or dock?

Lightning is the name Apple gives to the connection port used to connect its most recent iPhone, iPod touch or iPad models to the mains for charging, or to a computer for charging and sync. Older models - such as the iPad 2, which has since been discontinued - use the older 30-pin dock, which is wider.

Lightning dock, on an iPad mini 2 with Retina display

30-pin port, on an iPhone 4

What are Live Photos?

An appealing new feature announced by Apple at the launch of its iPhone 6s and iPhone 6s Plus. If you have this feature activated, your iPhone will automatically capture 1.5 seconds of video before you take a still photo, and 1.5 seconds after, thus preserving a 3-second video of the moment that can be activated at any time by using 3D Touch.

Read next: How to use Live Photos

What are Location Services?

Feature in iOS and Mac OS X that enables apps to determine your current location. Uses a mixture of GPS and triangulation of nearby Wi-Fi hotspots and Mobile data masts.

What is Lock?

Feature on iOS devices used to fix the display in either vertical or landscape orientation. Accessed via Control Centre.

What is Low Power Mode?

A cunningly streamlined mode available in iOS 9 and designed to prolong iPhone battery life. You will automatically be offered this mode when you hit 20 percent battery, but it can activated at any time via the Settings.

Low Power Mode makes your battery indicator turn yellowy orange.

See also: 34 tips to help boost iPhone battery life

What is Low Power Mode?

Tech jargon buster: M

Simon Jary's A to Z of Apple: Mmmmmmm… Apple

What is a Mac?

A type of personal computer made by Apple (that's right - technically a Mac is a PC too), at time of writing celebrating its 30th birthday. Check out our Mac reviews to find out more, but here's a summary of the range:

Apple laptops (or MacBooks) can be divided into the powerful MacBook Pro and the lighter MacBook Air. (Each of these are available in various screen sizes and component configurations.)

Apple makes three lines of Mac desktops: the general-purpose iMac, the cheaper, portable Mac mini, and the expensive, super-powerful Mac Pro. Again, both lines are available in various configurations.

What is a MacBook?

Apple's term for a Mac laptop computer. Several models are available, split into the more powerful MacBook Pro units, and the ultra-slimline MacBook Air models.

See: MacBook laptop reviews

MacBook Pro laptops

What is a Mac mini?

A small desktop computer sold without a keyboard, monitor or mouse. See Mac Mini 2014 preview.

What is a Mac Pro?

Apple's high-end desktop computer. Looks a bit like a shiny little bin but is a lot better at video editing. (See new Mac Pro review)

Mac Pro review

What is Mail?

Stock program used to read email. It's installed with Mac OS X and iOS devices.

What is a megapixel?

It's a measure of a digital camera's capacity to capture detail. A megapixel is a million pixels, so an 8Mp camera, such as the one in the iPhone 6 Plus, has eight million pixels.

If the camera used to take a digital image and the screen used to display it both have a large number of pixels, the image will as a general rule appear extremely sharp and detailed.

However, see this: The iPhone camera and the megapixel myth

What is multitasking?

In the general sense, of course, this simply means the ability to do more than one thing at once. But in the tech world it refers to running two programs at once - something that historically, iPads and iPhones have been unable to do. (You might think you've got two apps running at once, but for most intents and purposes every app except the one you've got open right now is frozen in a static state.)

In iOS 8 Apple added the ability for apps to refresh in the background, but iOS 9 adds proper multitasking - the ability to run two apps, and interact with them both at the same time, in split-screen. (This only works on the iPad Air 2 and iPad Pro.)

What is multitasking in iOS 9?

What is Multi-touch?

The iPhone and iPad display enables touch screen interaction using more than one finger (digit) at a time.

A good example of this can be seen in the iOS game Eliss Infinity, in which you have to move planets around the screen at great speed. You will generally be moving at least two or three planets at any one time, and the game can handle up to five fingers at the same time.

Eliss Infinity

Tech jargon buster: N

Simon Jary's A to Z of Apple: Apple's N of the road

What is News?

News is one of the features added to iPhones and iPads with the iOS 9 update. It's a sort of digest of news stories culled from a pre-selected list of providers. Apple describes News as "beautiful content from the world's greatest sources, personalised for you".

At time of writing we've not had a go on News because it hasn't been added to the public betas of iOS 9, but we're looking forward to testing it out in the final official release.

Want to know more about News? Read my colleague's far more detailed explanation, Apple's News app in iOS 9: All the news that fits, they print?

What is News in iOS 9?

What is Newsstand?

Program used to download and read digital versions of newspapers and magazines. It's one of the stock apps that are pre-installed in iOS, and you can't delete it from an iPhone or iPad unless you jailbreak. But at least you can hide it in a folder if you're not interested; in iOS 6 you couldn't even do that.

What is NFC?

NFC, or near-field communication, is a technology that enables devices to pass information across a very short distance. Typically just a couple of centimeters. Although it's called near field, the general idea is to allow devices to tap each other to exchange information.

One frequently talked-up use for NFC is to allow phones to act as payment devices, much like the latest generation of tap-to-pay credit cards. Android smartphones have offered this for some time, but Apple only joined the NFC party relatively recently, with its own NFC-reliant touch-payment system, Apple Pay.

What is Notification Centre?

Feature in iOS and Mac OS X that enables you to view recent messages and alerts on the device. On an iPhone or iPad, you access Notification Centre by swiping downwards with a finger from the top of the screen.

Tech jargon buster: O

Simon Jary's A to Z of Apple: Oh no! 'O' is for 'Out'

What is Objective C?

Programming language created by Apple and used to develop Mac OS X and iOS software.

Tech jargon buster: P

Simon Jary's A to Z of Apple: Apple gives Ps a chance

What is a phablet?

An ugly contraction of 'phone' and 'tablet', this refers to the very largest smartphones, generally with screens in the region of 5 or more inches diagonally from corner to corner. Apple currently sells two phablets: the iPhone 6 Plus (from 2014) and the iPhone 6s Plus (released in September 2015), both of which have 5.5in screens. Rival smartphone makers have been selling phablets for much longer.

What is Photo Booth?

Program for iOS and Mac OS X that captures self portraits. Often combined with humorous effects.

What is Photo Stream?

iCloud service that shares recently captured photographs across multiple iOS and Mac OS X devices.

What is 'pinch to zoom'?

Gesture made on iOS devices and Mac trackpads. Made by pinching finger and thumb together on screen, or 'unpinching' them apart. Often used to zoom in on items (web pages, photographs, and so on). Technically speaking it's usually the 'unpinch' that zooms into maps and so on, whereas the pinch zooms out, but we still call the feature 'pinch to zoom' in a general sense.

What is pocket dialling?

The irritating phenomenon whereby you accidentally ring someone up when your phone is in your pocket - the result of overly tight trousers, one would imagine.

Also known as butt dialling, apparently, and recently added to OxfordDictionaries.com.

What is Proactive?

Proactive is the (apparently unofficial) name for new contextually aware features in iOS 9. The system keeps tabs on when and where you use certain apps or contact certain people, for example, and offers quick links to those actions in the lock screen or search screen. It sounds a little sinister but can be a handy time-saver.

Read more on this subject: iOS 9 makes Siri more 'proactive' and adds video searchand How to use Proactive in iOS 9.

What is Push?

Push notifications are notifications that can be sent immediately to you on your iPhone. Push is often a type of e-mail service, as opposed to IMAP or POP. With Push enabled e-mails that are sent to your iPhone appear immediately on the device. The opposite of Push is Fetch, a system where the iPhone checks for e-mail in regular intervals (typically once every 15 minutes). iCloud is a Push service, so new e-mails and changes to the Calendar and Contacts are sent to other devices immediately.

Tech jargon buster: Q

Simon Jary's A to Z of Apple: Apple Qs round the block

What is QuickTime?

Video compression technology used by apple to distribute movies across the web. Also the name of a program used on Mac OS X to watch and share video clips.

Not to be confused with quick time events, which are those rubbish bits in computer games where you have to 'press X to escape from bag'.

Tech jargon buster: R

Simon Jary's A to Z of Apple: Apple gets the right Rs

What's the Refurbished store?

Apple's Refurbished store is great place to pick up bargains.

The products there are pre-owned, but Apple checks them over thoroughly and replaces any worn-out components before putting them on the store. You get a one-year warranty, too. It's the best place to find Macs and iPads that Apple no longer sells new, and always worth a look before buying new - there could be a bargain. The latest generation of products won't be on there, however, so don't expect a bargain on the most recent iPad Air, for instance.

Read more: Complete guide to buying a second-hand, old or refurbished iPhone

What is a Retina display?

Apple's marketing term for the sharp displays featured on many Mac OS X and most iOS devices. Features a high resolution (comparative to size of display) that packs around 300 pixels into an inch, although the pixel density required to qualify as Retina in Apple's book depends on how far the average user will hold the device from their face - so full-size iPads are rated as Retina at a lower pixel density than iPhones.

The pixel density of Retina displays is considered more than the human eye can pick out individually, so it's fooled (in theory) into thinking it's looking at a real thing, rather than a picture of the thing on a screen.

What is a Retina HD display?

What is a Retina HD display?

The step beyond Retina.

The only screens currently rated as Retina are those on the iPhone 6 and iPhone 6 Plus. It's not entirely clear what criteria are used to differentiate between Retina and Retina HD screens, but it evidently isn't pixel density, since the iPhone 6 has the same pixel density (326ppi) as its plain-Retina predecessors. (The iPhone 6 Plus, however, has a considerably higher spec: 401ppi.)

It seems that Retina HD is defined as offering wider viewing angles, better contrast, an improved polariser (which lets you view the screen more easily when wearing sunglasses) and a higher resolution - which in this case essentially translates to 'bigger screen'.

Read more: What are Retina and Retina HD displays, and are they worth the money?

Tech jargon buster: S

Simon Jary's A to Z of Apple: Apple's crazy S words

What is Safari?

Web browser software included with iOS and Mac OS X devices. It's the software that converts the code written by a website's designers into browsable text, pictures and dynamic content.

Other web browsers are available for both iOS and Mac OS X, such as Chrome, Firefox and Opera, although Safari will always remain the default browser on an unjailbroken iPhone or iPad; this means any time you click a link on Twitter or Mail iOS will open the link in Safari, even if you normally browse the web in Dolphin.

(See Safari tips and Alternatives to Safari: The best browsers for iPhone and iPad)

Web browsers

What's a screenshot?

A contraction of screen and snapshot, this simply means a static image of whatever is on a screen at a given time. It's useful for showing error messages and glitches to tech-savvy friends, for showing off photogenic moments in games, and (if you run a website for Mac, iPhone and iPad users) for illustrating tech tutorials, apps and games.

You can take a screenshot on a Mac by pressing Shift, Cmd and 4 and dragging the cross over the area you want to capture, but there are a few other techniques - capturing individual windows, the entire screen and so on - explained in that linked article.

To capture a screenshot on an iPhone or iPad, you simply need to press the Power/sleep/wake button (the one at the top) and the Home button (the one below the screen) at the same time.

Last of all, you can take a screenshot on Apple Watch by pressing the Digital Crown (the dial) and the side button at the same time.

What is the Settings app?

A pre-installed app in iOS that enables you to adjust system-wide settings - such as changing the desktop wallpaper, switching Wi-Fi or data roaming on or off, or turning down the screen brightness - or specific settings for individual apps. A few of the most frequently used settings, such as the brightness, volume, Airplane Mode and Do Not Disturb, can also be accessed via the Control Centre.

The Settings app icon is the one that looks like a load of grey cogs. (Mac OS X uses a similar icon for System Preferences.)

Settings icon in iOS 7

What is the Sleep/Wake button?

The button at top of iOS devices that enables you to wake up the device, or put it back to sleep. If you hold it down you can power the device down completely. Sometimes also called the power button.

The sleep/wake button seems somewhat prone to malfunctioning, unfortunately, but if your iPhone's sleep button isn't working, there is a clever fix.

What's a SIM?

The little chip in a phone or (if you want to add 3G capabilities) tablet that contains your 'cellular identity'. Comes in various sizes, most commonly micro-SIM and nano-SIM. We talk about the differences between these, which type is needed for each iPhone and iPad, and how to insert them, in our tutorial How to put a SIM card into a new iPad.

Mini-SIM, micro-SIM and nano-SIM

What is Siri?

Voice-recognition technology featured in more recent iPhones and iPads. (The iPad 3 and later, and the iPhone 4S and later, get access to Siri if they've updated to the most recent version of iOS.) Enables you to perform many features on the device without having to interact with the touchscreen.

If you've been having trouble with Siri, take a look at our Siri troubleshooting guide. And for a bit more fun, read our ever-popular Funny things to ask Siri.

What is Spotlight search?

Search technology found in iOS and Mac OS X devices that enables you to find many different types of information: contacts, documents, music files and so on. Can search through documents as well as by the file name.

What is the status bar?

The top bar running along the iOS devices. Displays many small icons related to the status of the device (Wi-Fi, Bluetooth, 3G and so on).

iOS 7 status bar

In this case, we can tell (reading from left to right): that the cellular signal is moderately strong (3 spots out of 5); that our carrier firm is 3; that we are connected to Wi-Fi, and that the Wi-Fi signal is strong (three bars out of three). Then on the righthand side of the screen: we are in Do Not Disturb mode (that's the moon symbol); we are using Bluetooth; that our battery is at 58% power (this is also indicated visually); and that we are currently charging the iPad. 

For more information on all the symbols that can appear on an iPad or iPhone screen, take a look at our article 'What does it mean on an iPhone when…'

Tech jargon buster: T

Simon Jary's A to Z of Apple: It's T time for Apple

What is a tap?

As well as an item of bathroom plumbing, a tap is a gesture used on iOS whereby you quickly place and then remove a single finger on the screen. Comparable to a 'left-click' used on a desktop mouse or trackpad.

What are taptics, or a 'taptic engine'?

A contraction of 'tap' and 'haptics', this is Apple's take on the haptic concept outlined above. Most famously, a taptic engine in the Apple Watch vibrates in such a way when you get an alert that it feels like it's tapping you on the wrist.

What is Time Capsule?

A device sold by Apple that combines a wireless router with a hard drive. Enables users to wirelessly backup Mac computers.

What is Time Machine?

Backup software made by Apple - be sure to back up your documents and files so you're not caught out when tech disaster strikes. We discuss how to get the most out of Time Machine in the following tutorials:

What is a troll?

On the internet, this is a pejorative term that originally referred to forum users who were only interested in starting arguments.

These days people use the term troll more loosely, no longer distinguishing between those who are willing to argue to defend their (possibly extreme) views, and the original trolls who went out looking for arguments, sometimes pretending to have extreme views they didn't really believe in. Sometimes it seems to mean 'people I don't agree with'.

For Macworld's take on the concept, see our article Best (and worst) of the Android fanboys: Our 15 favourite troll comments.

Outside the internet, a troll is a large, ugly beast that may or may not turn to stone when exposed to sunlight.

Tech jargon buster: U

Simon Jary's A to Z of Apple: U is for U2

What is a UDID?

A UDID (which stands for unique device identifier) is a 40-character alphanumeric code allocated to every iPhone, iPad or iPod touch. If you've agreed to beta-test some pre-release software you may be asked for your UDID, which lets an app developer bypass the normal App Store download process.

More here: How to find our your iPhone (or iPad) UDID: What's my iPhone's UDID?

How to find out your iPhone UDID

What is a universal app?

If we're talking iPad and iPhone apps, this is simply an app that has been designed in such a way that a single app will run on both iPhone and iPad (and iPod touch and iPad mini, for that matter).

Some apps only work on iPad (and iPad mini) or iPhone (and iPod touch), whereas other developers write separate apps for each device. But a universal app works on them all (provided they are recent enough - the developers should specify which particular models the app is compatible with). If you buy a universal app on your iPad, you can download it to your iPhone at no extra cost. Universal apps are therefore A Good Thing.

We explain the finer points of universal apps in our tutorial - which also covers how to run iPhone apps on iPads, and how to run iPad apps on iPhones.

What is unlocking?

Phone unlocking is a process whereby you make it possible to use any SIM rather than just the one you received from your mobile provider.

Many people think iPhone unlocking is difficult, or illegal, and the suspect-looking shops that specialise in SIM card unlocking don't do much to suggest that iPhone unlocking is a legitimate practice. But you can get free iPhone unlock codes from your mobile phone operator.

Here's how to unlock your iPhone.

Tech jargon buster: W

Simon Jary's A to Z of Apple: Wow! www.apple.com

What is Wi-Fi?

Wireless technology used to transmit data from a router to a mobile device (such as a laptop, smartphone or tablet).

What is WWDC? (What does WWDC stand for?)

WWDC stands for Worldwide Developer Conference, and is the annual get-together where Apple reveals its major operating system updates to app developers (and to the watching media, of course) and then runs lots of workshops and tutorials.

Most recent WWDC was WWDC 2015, where Apple showed off iOS 9 and Mac OS X El Capitan, and announced that Apple Pay was coming to the UK.

Tech jargon buster: X

Simon Jary's A to Z of Apple: Apple's X Factor Talent Show

What is Xcode?

Mac OS X software development environment. A program distributed for free by Apple that enables users to create Mac OS X and iOS software.