/ Dictionary / Index A A.I.M.U.: Meaning and Definition of Find definitions for: A.I.M.U. Pronunciation: [key] American Institute of Marine Underwriters. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. aimless ain Related Content Daily Word Quiz: penurious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language