(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.