/ Dictionary / Index T T number: Meaning and Definition of Find definitions for: T number Pronunciation: [key] — Photog. Photog. one of a series of calibrations of lens openings according to the intensity of the light actually transmitted by the lens. Symbol: T Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. TNT to Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language