"ARCOS"?

"Distro"?

It's not called ARCOS. It's AROS: (originally) the Amiga Research Operating System. (Due to a trademark claim, it is now the recursive AROS Research OS.)

AROS is not a distro; the word "distro" implies Linux. This is not Linux, nor is it even Unix.

Arguably it is a distribution of AROS, but the term is confusing and misleading.