/ Dictionary / Index D directional microphone: Meaning and Definition of Find definitions for: direc'tional mi'crophone Pronunciation: [key] a microphone that has a greater sensitivity to sounds coming from a particular area in front of it: used to eliminate unwanted sounds. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. directional derivative directional signal 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