Google Play
Google Play
Google Play, (formerly known as the AndroidMarket), is a digital application distribution platform for Android and an online electronics and digital media store developed and maintained by Google.

The service allows users to browse and download music, magazines, books, movies, television programs, and applications published through Google. Users can also purchase Chromebooks, Google Nexus-branded mobile devices, other Google-branded hardware, and accessories through Google Play.

Applications are available either for free or at a cost. They can be downloaded directly to an Android or Google TV device through the Play Store mobile app, or by deploying the application to a device from the Google Play website. These applications are generally targeted to users based on a particular hardware attribute of their device, such as a motion sensor (for motion-dependent games) or a front-facing camera (for online video calling).
Reference
Wikipedia
Online Application Stores
Apple App Store
Google Play
Microsoft Store