The story
Turing introduced "c-machines" in his 1936-37 paper "On Computable Numbers" to represent machines that, upon reaching a certain state, require an "arbitrary choice" to be made.
Etymology from Wiktionary, CC BY-SA 4.0.
choice machine
Today it means: A type of computing model where the next action is not entirely determined by its current state and the symbol it reads. Full definition →