/ Dictionary / Index L letter box: Meaning and Definition of Find definitions for: let'ter box" Pronunciation: [key] — Chiefly Brit. Chiefly Brit. a public or private mailbox. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. letter bomb letter-card 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