/ Dictionary / Index L lieutenant commander: Meaning and Definition of Find definitions for: lieuten'ant comman'der Pronunciation: [key] — U.S. Navy. U.S. Navy. a commissioned officer ranking next below a commander and next above a lieutenant. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lieutenant colonel lieutenant general 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