/ Dictionary / Index M main-topmast: Meaning and Definition of Find definitions for: main-top•mast Pronunciation: (mān"top'mast", -mäst"Naut.mān"top'm&schwast), [key] — n. Naut. the mast next above the main lower mast. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: main-topmast (Thesaurus) main-topgallantmast main-topsail Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language