/ Dictionary / Index Z zygosis: Meaning and Definition of Find definitions for: zy•go•sis Pronunciation: (zī-gō'sis, zi-), [key] — n. Biol. the union of two gametes; conjugation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. zygopteran zygosity Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language