noun, plural: polyps
(1) (zoology) The hollow, columnar, sessile form of Cnidarians (as opposed to the medusa form)
(2) (pathology) An abnormal (usually benign) pedunculated growth, protruding from a mucous membrane
(zoology) Cnidarians take two body forms: polyp and medusa. The polyp body form is sessile, elongated, and hollow. Their lower end is attached to a substratum. Their free upper end is where the mouth and the tentacles are located. One of the major differences between polyp and medusa is their mode of reproduction. Polyps generally reproduce asexually (by budding) whereas medusae, by sexual reproduction. Some Cnidarians take a polyp body form (e.g. sea anemones and corals); others, medusa (e.g. scyphozoans). But there are also Cnidarians that exhibit both polyp and medusa stages in their life cycle (e.g. most hydrozoans).
Word origin: Greek polupous, from polus (many) + pous (foot)
- medusa (zoology)