/ Dictionary / Index L long johns: Meaning and Definition of Find definitions for: long' johns" Pronunciation: [key] — (used with a pl. v.) Informal. (used with a pl. v.)Informal. long underwear, esp. for winter use. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. longitudinal wave long jump Related Content Daily Word Quiz: fresco Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language