/ Dictionary / Index S second lieutenant: Meaning and Definition of Find definitions for: sec'ond lieuten'ant Pronunciation: [key] — U.S. Mil. U.S. Mil. an Army, Air Force, or Marine officer of the lowest commissioned rank. Cf.(def. 4). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. second lien secondly Related Content Daily Word Quiz: sinister Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language