Breadcrumb Home > Dictionary > Index M mesonephros: Meaning and Definition of Find definitions for: mes•o•neph•ros Pronunciation: (mez"u-nef'ros, mes"-, mē"zu-, -su-), [key] — pl. -roi one of the three embryonic excretory organs of vertebrates, becoming the functional kidney of fishes and amphibians and becoming part of the tubules or ductules in the reproductive systems of higher vertebrates. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. meson mesopause ✖ Related Content Daily Word Quiz: rococo Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language