/ Dictionary / Index M mesocyclone: Meaning and Definition of Find definitions for: mes•o•cy•clone Pronunciation: (mez"u-sī'klōn, mes"-, mē"zu-, -su-), [key] — n. Meteorol. a small cyclone that arises near a thunderstorm and is sometimes associated with the occurrence of tornadoes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mesocratic mesoderm Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language