/ Dictionary / Index A acton: Meaning and Definition of Find definitions for: ac•ton Pronunciation: (ak'tun), [key] — n. Armor. a quilted garment worn under mail in the 13th and 14th centuries; gambeson. Ac•ton Pronunciation: (ak'tun), [key] — n. (John Emerich Edward Dalberg-Acton, 1st Baron), 1834–1902, English historian. a former municipal borough in SE England, now part of the London borough of Ealing: center of Puritanism at the time of Cromwell. a city in NE Massachusetts. 17,544. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. actomyosin actor Related Content Daily Word Quiz: divulge Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language