/ Dictionary / Index A Atchison: Meaning and Definition of Find definitions for: Atch•i•son Pronunciation: (ach'u-sun), [key] — n. a city in NE Kansas, on the Missouri River. 11,407. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ATC ate Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language