/ Dictionary / Index D direction number: Meaning and Definition of Find definitions for: direc'tion num"ber Pronunciation: [key] — Math. Math. the component of a vector along a given line; any number proportional to the direction cosines of a given line. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. direction finder directive Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language