/ Dictionary / Index A aperture mask: Meaning and Definition of Find definitions for: ap'erture mask" Pronunciation: [key] — Television. Television. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. aperture aperture-priority Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language