新教材 | 2019 北师大版 高中英语 B2-U4-L2 APPS（附：A Beginner's Guide to Apps）

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Definition of app

especially : an application designed for a mobile device (such as a smartphone)

Health-insurance companies and government officials alike are drawn to the ability of smartphone apps to reach tough-to-access patients, to effect long-term lifestyle changes, and to do it all at a very low cost.

A Beginner's Guide to Mobile Apps

An app is a software program running on any platform

by Marziah Karch 

The word "app" is an abbreviation for "application". It's a piece of software that can run through a web browser or offline on your computer, and on a smartphone phone, tablet or other electronic devices, including smart TVs and smartwatches. Apps may or may not have a connection to the internet.

An app is a modern term for a software application, and it is most often used in reference to a mobile app or a small piece of software that runs on a website. It's typically used to describe anything that isn't a full-fledged software program, but even that line has become blurred.

Types of Apps

There are three main types of apps: desktop, mobile, and web.

Desktop apps are usually much fuller than mobile apps and consist of all the features of a program, whereas the mobile equivalent is a simpler and easier-to-use version.

This makes sense when you consider that most desktop and web apps are built to be used with a mouse and keyboard along with a large display, but mobile apps are intended to be accessed with a finger or stylus on a small screen.

Web apps might be full of features too, but they have to leverage the capabilities of the internet connection and web browser program, so while some are heavy duty and can perform well like mobile or desktop programs, most web apps are lightweight for a reason.

If an app is a mix between a web app and a desktop app, it might be called a hybrid app. These are apps that have an offline desktop interface and direct access to hardware and other connected devices, but also an always-on connection to the internet for quick updates and access to internet resources.

Examples of Apps

Some apps exist in all three forms and are available as not only mobile apps but also desktop and web apps.

The Adobe Photoshop image editor is a full software program that runs on your computer, but Adobe Photoshop Sketch is a mobile app that lets you draw and paint on a portable device. It's a condensed version of the desktop application. The same is true with the web app called Adobe Photoshop Express Editor.

Another example is Microsoft Word. It's available for computers in its most advanced form but also on the web, by subscription, and via a mobile app.

Those two examples are of apps that exist in all three app forms, but that isn't always the case.

For example, you can get to your Gmail messages through the official Gmail.com website and Gmail mobile app, but there isn't a desktop program from Google that lets you access your mail. In this case, Gmail is both a mobile and web app but not a desktop app. You can add it or remove it as desired.

Others (often games) are similar in that there are both mobile and web versions of the same game but maybe not a desktop app, or there might be a desktop version of the game, but it's not available on the web or as a mobile app.

Where to Get Apps

In the context of mobile apps, almost every platform has a repository where its users can download both free and paid apps. These are normally accessible through the device itself or a website so that the app can be queued up for download the next time the user is on the device.

For example, the Google Play store and Amazon's Amazon Appstore are two places where Android users can download mobile apps. iPhones, iPod Touch devices, and iPads can get apps through the App Store straight from their devices.

Desktop apps are more widely available from unofficial sources such as Softpedia and FileHippo.com, but some official app repositories include the Mac App Store for macOS apps and the Windows Store for Windows apps.

Web apps load within a web browser and don't need to be downloaded, unless you're talking about something like Chrome Apps that are downloaded to your computer but then run small web-based apps through the chrome://apps/ URL, such as Video stream.

Google refers to its online services as apps, but the company also sells a specific suite of services known as Google Apps for Work. Google has an application-hosting service called Google App Engine, which is a part of the Google Cloud Platform.