Coroutines are computer program components that can be suspended and resumed — generalizing subroutines — for cooperative multitasking. Coroutines are well-suited for implementing familiar program components such as cooperative tasks, exceptions, event loops, iterators, infinite lists and pipes.
They have been described as "functions whose execution you can pause".1
Melvin Conway coined the term coroutine in 1958 when he applied it to the construction of an assembly program.2 The first published explanation of the coroutine appeared later, in 1963.3