Android is one of the two main operating systems seen in tablets and other mobile devices, the other being Apple’s proprietary iOS. More devices run Android and there is more content available for it than for Apple devices.
The All-New Fire 7 Kids Edition is an Android tablet; however, it isn’t a pure Android tablet. Instead, it runs on Amazon’s own offshoot of the Android operating system, Fire OS (which promotes content available through Amazon’s services). As such, it doesn’t have access to the entire Android ecosystem. The tablet can get content from the Amazon Appstore out of the box but Google Play is not supported without some modification.