/ Dictionary / Index E explementary angle: Meaning and Definition of Find definitions for: ex'plemen'tary an'gle Pronunciation: [key] — Math. Math. either of two angles that added together produce an angle of 360°. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. explement expletive Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language