POL'YPUS, noun [Gr. many and foot.]

1. Something that has many feet or roots.

2. In zoology, a species of fresh water insect, belonging to the genus Hydra and order of zoophytes. Of this animal it is remarkable, that if cut into pieces, each part will shoot out a new head and tail and become a distinct animal. The general character of this animal is, it fixes itself by its base, is gelatinous, linear, naked, contractile, and capable of changing place.

The common name of all those small gelatinous animals, whose mouth is surrounded by tentacula or feelers, (whence the name, )

and conducts to a simple stomach, or one followed by intestines in the form of vessels. They constitute a distinct class or order of zoophytes, and include those compound animals, with a fixed and solid stem, which were formerly regarded as marine plants.

3. A concretion of blood in the heart and blood vessels.

4. A tumor with a narrow base, somewhat resembling a pear;

found in the nose, uterus, etc.