What is an Android?
The term Android may mean two different things: a humanoid robot (not to be confused with a cyborg, which is a human with cybernetic body parts), or the name of a Linux-based operating system for smartphones sponsored by Google.
Is The Android Operating System Open Source?
The Android that people normally have installed in their smartphones isn't completely open source, but it's based upon an open source operating system called "Android Open Source Project" or AOSP [https://source.android.com/] (accessed 2025-03-26).
In Google's Android, you will have various Google software installed by default, such as the Google search box, the Google Play Store, etc., while in the AOSP you are free to install and uninstall whatever you want but the starting point has barely anything functional. See [https://www.youtube.com/watch?v=-hlRB2izres] (accessed 2025-03-26) for a review of AOSP.
This isn't an uncommon scheme. For example, Microsoft's Visual Studio Code uses the same scheme, with its branding and telemetry added on top of its open source version [Is VS Code Open Source?].
Is Android a Linux Distro?
Well, technically, yes, but nobody calls Android a Linux distro.