/ Dictionary / Index L lm-hr: Meaning and Definition of Find definitions for: lm-hr Pronunciation: [key] — Optics. Optics. lumen-hour; lumen-hours. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. LM LMT Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language