/ Dictionary / Index E extensity: Meaning and Definition of Find definitions for: ex•ten•si•ty Pronunciation: (ik-sten'si-tē), [key] — n. the quality of having extension. the attribute of sensation from which the perception of spatial extension is developed. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. extension tube extensive Related Content Daily Word Quiz: pudgy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language