Source : Webster's Revised Unabridged Dictionary (1913)

Zygosperm \Zyg"o*sperm\, n. [Gr. ? a yoke + E. sperm.] (Bot.)
   A spore formed by the union of the contents of two similar
   cells, either of the same or of distinct individual plants.
   Zygosperms are found in certain orders of alg[ae] and fungi.