/ Dictionary / Index M millboard: Meaning and Definition of Find definitions for: mill•board Pronunciation: (mil'bôrd", -bōrd"), [key] — n. Bookbinding. a strong, thick pasteboard used to make book covers. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: millboard (Thesaurus) Millay Millbrae 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