"Context" manipulation is one of big topic and there are many related terminologies (academic, language/implementation specific, promotion terminologies). In fact, there is confusing. In few minutes I remember the following related words and it is good CS exam to describe each :p Thread (Ruby) Green thread (CS terminology) Native thread (CS terminology) Non-preemptive thread (CS terminology) Preemptive thread (CS terminology) Fiber (Ruby/using resume/yield) Fiber (Ruby/using transfer) Fiber (Win32API) Generator (Python/JavaScript) Generator (Ruby) Continuation (CS terminology/Ruby, Scheme, ...) Partial continuation (CS terminology/ functional lang.) Exception handling (many languages) Coroutine (CS terminology/ALGOL) Semi-coroutine (CS terminology) Process (Unix/Ruby) Process (Erlang/Elixir) setjmp/longjmp (C) makecontext/swapcontext (POSIX) Task (...)