/ Dictionary / Index A AST: Meaning and Definition of Find definitions for: AST Pronunciation: [key] Atlantic Standard Time. See under Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Assyro-Babylonian Astaire Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language