GILL, n.

1. The organ of respiration in fishes, consisting of a cartilaginous or bony arch, attached to the bones of the head, and furnished on the exterior convex side with a multitude of fleshy leaves, or fringed vascular fibrils, resembling plumes, and of a red color in a healthy state. The water is admitted by the gill-opening, and acts upon the blood as it circulates in the fibrils. Other animals also breathe by gills, as frogs in their tadpole state, lobsters, &c.

Fishes perform respiration under water by the gills.

2. The flap that hangs below the beak of a fowl.

3. The flesh under the chin.

4. In England, a pair of wheels and a frame on which timber is conveyed. [Local.]