/ Dictionary / Index L lumen-hour: Meaning and Definition of Find definitions for: lu•men-hour Pronunciation: (l'mun-our", -ou"ur), [key] — n. Optics. a unit of luminous energy, equal to that emitted in 1 hour by a light source emitting a luminous flux of 1 lumen. Abbr.: lm-hr Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lumen Lumholtz's kangaroo Related Content Daily Word Quiz: menagerie Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language