1. (n.) Any projection or division, especially one of a somewhat rounded form

2. (n.) A rounded projection or division of a leaf.

3. (n.) A membranous flap on the sides of the toes of certain birds, as the coot.

4. (n.) A round projecting part of an organ, as of the liver, lungs, brain, etc.

5. (n.) The projecting part of a cam wheel or of a non-circular gear wheel.