1. a vascular, red cutaneous structure attached in a sagittal plane to the dorsum of the skull of domestic fowl. It consists of a base attached to the skull, a central mass called the body, a backward projecting blade and upward projecting points.
2. part of mechanical sheep shears.
3. see ctenidium.

• buttercup c. — has no blade and is divided sagittally. It is cup-shaped with points arranged around the cup.
• cushion c. — a low, small, oval, smooth body with no points.
• nasal c. — the red, vascular structure across the base of the beak in the turkey. Called also snood, frontal process.
• pea c. — has three blades with a row of points arising from each.
• rose c. — a low elongated comb from which many small points arise. There is a backward projecting spike in lieu of a blade.
• Silkie c. — similar to the V-comb but without points.
• single c. — has all of the components without variation; the standard comb.
• strawberry c. — a small, oval, flattened comb with a wrinkled surface.
• V-c. — two large, conical points diverge from a sizeable body. Usually accompanies a crest of feathers.