/ Dictionary / Index P pillar box: Meaning and Definition of Find definitions for: pil'lar box" Pronunciation: [key] — Brit. Brit. a pillarlike box in which letters are deposited for collection by mail carriers; mailbox. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pillar-and-breast pillaret Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language