a. - Pertaining to, or resembling, an animal.
n. - An organic body or cell having locomotion, as a spermatic cell or spermatozooid.
n. - An animal in one of its inferior stages of development, as one of the intermediate forms in alternate generation.
n. - 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.