Is thread a windows concept?

c#, multithreading, operating-system, windows

Solution

Short answer: No, it's not solely a Windows concept, and the concept has been around for quite a long time.

Problem

So i was reading "CLR via C#" and found this line "A thread is a Windows concept whose job is to virtualize the CPU". Really? Was single\multi thread originally from Windows? Googling for justification did not help and hence seeking help from the community.

Original source