/ Dictionary / Index A aplomb: Meaning and Definition of Find definitions for: a•plomb Pronunciation: (u-plom', u-plum'), [key] — n. imperturbable self-possession, poise, or assurance. the perpendicular, or vertical, position. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: aplomb (Thesaurus) aplite apmt. Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language