Definition of "automaton"

Nick had heard her play through the very beginning of it a dozen times, until he was screaming at her in his head to go on. Well, now she did, watching her own hands busying up and down the keyboard as if they were astonishing automata that she had wound up and set in motion, in perfect synchrony, to produce this silvery flow of sound.

2004, Alan Hollinghurst, chapter 9, in The Line of Beauty […], 1st US edition, New York, N.Y.: Bloomsbury Publishing

A departure from principle in one instance becomes a precedent for a second, that second for a third, and so on 'til the bulk of the society is reduced to be mere automatons of misery, to have no sensibilities left but for sinning and suffering.

July 12, 1816, Thomas Jefferson, letter to Samuel Kercheval Monticello

—to the young man who filled a place at table as the permitted, not invited, the unrewarded labourer for an ungrateful taskmaster—the handsome dangler, allowed to join in a quadrille, on the condition of being an automaton before and after—the listener to young members, and old women of rank—the person who must bore nobody, but whom every body had a right to bore!

1838 (date written), L[etitia] E[lizabeth] L[andon], “(please specify the page)”, in Lady Anne Granard; or, Keeping up Appearances. […], volume I, London: Henry Colburn, […], published 1842, pages 228–229