Google has announced that Android Pay will now be integrated with Google Pay, which means the name of the app on your phone will also change. As you perform app updates in the next few days, expect Android Pay to disappear from your app drawer or home screen and be replaced with Google Pay.
Google Pay will bring better integration with other Google features, such as allowing payment on certain websites. The app is getting a makeover, bringing shopping info and gift card / rewards card management straight from the app. Read more at Google’s Blog.