/ Dictionary / Index M Mare Cimmerium: Meaning and Definition of Find definitions for: Ma're Cim•mer'i•um Pronunciation: (si-mēr'ē-um), [key] (Cimmerian Sea) an area in the southern hemisphere 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 Chronium mare clausum Related Content Daily Word Quiz: exemplary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language