Alt text: meme with the 'Always has been' format Linux, MacOS, OpenBSD and ChromeOS logos on top of the Earth The first astronaut says 'Wait, it's all Unix?' A Windows logo, on top of the second astronaut. The second astronaut says 'Always has been' and points a gun to the first astronaut.
UNIX is trademarked by 'The Open Group', Unix is not. ๐
To make things more confusing, according to German Wikipedia, Unix is used for Unix-like OSes which are not officially UNIX-certified. ๐ตโ๐ซ