Android is Linux, but doesn't have your traditional GNU or minimal busybox userland that you'd expect. Debian GNU/kFreeBSD is Debian, but it isn't Linux. Mac

Android is Linux, but doesn't have your traditional GNU or minimal busybox userland that you'd expect. Debian GNU/kFreeBSD is Debian, but it isn't Linux. Mac OS X with GNU tools via MacPorts/Fink/Homebrew is OS X with a GNU userland, but it isn't Linux. Windows 10 with an Ubuntu userland is Ubuntu, but it isn't Linux. Linux is a kernel.