\O"vum\, n.; pl. L. {Ova}, E. {Ovums}. [L., an egg. See
{Oval}.]
1. (Biol.) A more or less spherical and transparent mass of
   granular protoplasm, which by a process of multiplication
   and growth develops into a mass of cells, constituting a
   new individual like the parent; an egg, spore, germ, or
   germ cell. See Illust. of {Mycropyle}.
Note: The ovum is a typical cell, with a cell wall, cell
      substance, nucleus, and nucleolus. In man and the
      higher animals the cell wall, a vertically striated
      membrane, is called the zona pellucida; the cell
      contents, the vitellus; the nucleus, the germinal
      vesicle; and the nucleolus, the germinal spot. The
      diameter of the ripe ovum in man and the domestic
      animals varies between 1-200 and 1-120 of an inch.
2. (Arch.) One of the series of egg-shaped ornaments into
   which the ovolo is often carved. --Gwilt.