oospore

from WordNet (r) 3.0 (2006)

oospore
    n 1: a thick-walled sexual spore that develops from a fertilized
         oosphere in some algae and fungi

from The Collaborative International Dictionary of English v.0.48

Oospore \O"o*spore\, n. [Gr. w,'o`n an egg + ? a seed.] (Bot.)
   (a) A special kind of spore resulting from the fertilization
       of an oosphere by antherozoids.
   (b) A fertilized oosphere in the ovule of a flowering plant.
       [1913 Webster]