Source : Webster's Revised Unabridged Dictionary (1913)

Oculus \Oc"u*lus\, n.; pl. {Oculi}. [L., an eye.]
   1. An eye; (Bot.) a leaf bud.

   2. (Arch.) A round window, usually a small one.

Source : WordNet®

oculus
     n : the organ of sight [syn: {eye}, {optic}]
     [also: {oculi} (pl)]