/ Dictionary / Index S semibasement: Meaning and Definition of Find definitions for: sem•i•base•ment Pronunciation: (sem"ē-bās'munt, sem"ī-, sem'ē-bās"-, sem'ī-), [key] — n. a basement partly above ground, as in a house built on a slope. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. semiautonomy semibituminous coal Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language