/ Dictionary / Index L lapse rate: Meaning and Definition of Find definitions for: lapse' rate" Pronunciation: [key] — Meteorol. Meteorol. the rate of decrease of atmospheric temperature with increase of elevation vertically above a given location. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lapsed lapsible Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language