Source : Webster's Revised Unabridged Dictionary (1913)

Zooid \Zo"oid\, a. [Zo["o]- + -oid.] (Biol.)
   Pertaining to, or resembling, an animal.

Zooid \Zo"oid\, n.
   1. (Biol.) An organic body or cell having locomotion, as a
      spermatic cell or spermatozooid.

   2. (Zo["o]l.)
      (a) An animal in one of its inferior stages of
          development, as one of the intermediate forms in
          alternate generation.
      (b) One of the individual animals in a composite group, as
          of Anthozoa, Hydroidea, and Bryozoa; -- sometimes
          restricted to those individuals in which the mouth and
          digestive organs are not developed.

Source : WordNet®

zooid
     n : one of the distinct individuals forming a colonial animal
         such as a bryozoan or hydrozoan