a piece of software that you can download to a device such as a smartphone or tablet, for example to look up information or to play a game（下载到智能手机或平板电脑等设备上使用的）应用软件
You first need to install the app on your device.您首先需要在设备上安装该应用程序。
to download/launch an app下载/启动应用
to build/develop an app开发/开发应用
Have you got the dictionary app on your phone?你的手机上有这个词典的应用软件吗？
Gaming today is all about mobile app downloads.今天的游戏全部与移动应用程序下载有关。
app developers应用程式开发人员
The app is available on/in the app store.该应用程序可在应用程序商店内/中使用。