/ Dictionary / Index M Mare Boreum: Meaning and Definition of Find definitions for: Ma're Bo're•um Pronunciation: (bôr'ē-um, bōr'-), [key] (Northern Sea) an area near the north pole of Mars, appearing as a dark region when viewed telescopically from the earth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Mare Australe Mare Chronium Related Content Daily Word Quiz: tactful Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language