O"o*sphere (?), n. [Gr. an egg + E. sphere.]
An unfertilized, rounded mass of protoplasm, produced in an oogonium.
⇒ After being fertilized by the access of antherozoids it becomes covered with a cell wall and develops into an oospore, which may grow into a new plant like the parent.
An analogous mass of protoplasm in the ovule of a flowering plant; an embryonic vesicle.
© Webster 1913.