/ Dictionary / Index S semiminor axis: Meaning and Definition of Find definitions for: sem'i•mi'nor ax'is Pronunciation: (sem'ē-mī'nur, sem'ī-, sem"ē-, sem"ī-), [key] one half the minor axis of an ellipse. one half the minor axis of the ellipse that one celestial body describes around another, as a planet around the sun. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. semimicroanalysis semimonthly Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language