The Collaborative International Dictionary of English v.0.48:

Ovoid \O"void\, Ovoidal \O*void"al\, a. [Ovum + -oid: cf. F.
   ovo["i]de.]
   Resembling an egg in shape; egg-shaped; ovate; as, an ovoidal
   apple.

   Syn: oviform.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ovoid \O"void\, n.
   A solid resembling an egg in shape.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ovoid
    adj 1: rounded like an egg [syn: egg-shaped, elliptic,
           elliptical, oval, oval-shaped, ovate, oviform,
           ovoid, prolate]
    n 1: an egg-shaped object