An automaton was a relatively self-operating machine or mechanism designed to automatically follow or respond to predetermined instructions.
Webster's 24th Century Dictionary, Fifth Edition, defined an android as an automaton made to resemble a Human being. (TNG: "The Measure Of A Man")
In 2369, Captain Jean-Luc Picard recalled when Hugh was separated from the Borg Collective and began to grow and evolve into something other than an automaton and become a person. (TNG: "Descent")
In 2373, Riley Frazier assured Chakotay that she, Orum, and the others of the Cooperative were individuals with distinct personalities and were not going to turn Chakotay into some kind of automaton. (VOY: "Unity")
That same year, The Doctor referred to holograms inside a holodeck version of the Paxau Resort as automatons and mannequin simulacra with no secrets to reveal. (VOY: "Darkling")
In 2374, there was a disagreement between Seven of Nine and B'Elanna Torres in the USS Voyager's mess hall where Torres referred to Seven as an automaton and employed a series of profane Klingon insults. (VOY: "Concerning Flight")