Conceptually yes, but note that in Linux there is no such thing as a thread. Only processes. Some of those processes happen to share an address space and belong to a thread-group (TGID), but they are all processes.

This only really matters when you're trying to understand how PID, PPID, and TGID fit together and why there is no TID, though.

True, but Linux and UNIX are not the same thing, even though many keep mixing it up.

Actually, Linux is very explicit about not being a UNIX.

However, the topic would appear to be Windows, Linux and potentially also macOS. That's what the benchmarks are about. No one mentioned other OS's.

Which is why no one should use it as an example how UNIX works.

No one is! You're the one who brought up UNIX. The rest of us is commenting on a benchmark of specifically Windows, Linux and macOS. Only one of those was temporarily considered UNIX, and most disagreed with the label.