/ Dictionary / Index L long-day: Meaning and Definition of Find definitions for: long-day Pronunciation: (lông'dā', long'-), [key] — adj. Bot. requiring a long photoperiod in order to flower. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. longcloth Long Day's Journey Into Night* Related Content Daily Word Quiz: wary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language