automaton (n.)

1610s, "a self-acting machine;" 1670s, "a living being acting mechanically," from Latin automaton (Suetonius), from noun use of Greek automaton, neuter of automatos "self-acting," from autos "self" (see auto-) + matos "thinking, animated, willing," from PIE *mn-to-, from root *men- (1) "to think."

An automaton is defined as something which can only act as it is acted on. The meaning of the word is at variance with its etymology, but this need not mislead us. [Joseph John Murphy, "Habit and Intelligence," 1879]