A skin tag, or acrochordon (pl. acrochorda), is a small benign tumor that forms primarily in areas where the skin forms creases (or rubs together), such as the neck, armpit and groin. They may also occur on the face, usually on the eyelids.
Warts are typically small, rough, hard growths that are similar in color to the rest of the skin.
A corn (or clavus, plural clavi or clavuses) is a distinctively shaped callus of dead skin that usually occurs on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsal surface of toes or fingers. They can sometimes occur on the thicker skin of the palms or bottom of the feet.
Corns form when the pressure point against the skin traces an elliptical or semi-elliptical path during the rubbing motion, the center of which is at the point of pressure, gradually widening. If there is constant stimulation of the tissue producing the corns, even after the corn is surgically removed, the skin may continue to grow as a corn.