Google today announced that the Android Market, Google Music and the Google eBookstore is now a part of Google Play. Google will be upgrading the Android Market app to the Google Play Store app over the coming days on Android phone or tablet.
Google also says "Your videos, books and music apps (in countries where they are available) will also be upgraded to Google Play Movies, Google Play Books and Google Play Music apps. The music, movies, books and apps you’ve purchased will continue to be available to you through Google Play—simply log in with your Google account like always."
"In the U.S., music, movies, books and Android apps are available in Google Play. In Canada and the U.K., we’ll offer movies, books and Android apps; in Australia, books and apps; and in Japan, movies and apps. Everywhere else, Google Play will be the new home for Android apps."
Source:- Google Play