/ Dictionary / Index R residence time: Meaning and Definition of Find definitions for: res'idence time" Pronunciation: [key] Also calledthe length of time a substance remains in the adsorbed, suspended, or dissolved state. the length of time radioactive material, as gas or particles, remains in the atmosphere after detonation of a nuclear device. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. residence residency Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language