1. A body form of a cnidarian, such as a hydra or coral, that is cylindrical in shape, has a mouth usually surrounded by tentacles at one end, and is often attached to something at the other end.
2. A usually nonmalignant growth or tumor protruding from the mucous lining of an organ such as the nose, bladder, or intestine, sometimes causing obstruction.
[Middle English polip, nasal tumor, from Old French polipe, from Latin pōlypus, cuttlefish, nasal tumor, from Greek polupous, poulupous : polu-, poly- + pous, foot; see ped- in the Appendix of Indo-European roots.]
(click for a larger image)polyp
pedunculate polyp (top) and sessile polyp (bottom) in a section of large intestine
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