/ Dictionary / Index L lag line: Meaning and Definition of Find definitions for: lag' line". Pronunciation: [key] See under (def. 6). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Laghouat -lagnia Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language