Skin tag: A small tag of skin that may be squat (sessile) or on a stalk (a peduncle). Skin tags commonly occur on the eyelids, neck, armpits, upper chest, and groin. This tiny benign tumor of the skin usually causes no symptoms unless it is repeatedly irritated as, for example, by a collar. Treatment may involve freezing the skin tag with liquid nitrogen or cutting off the skin tag with a scalpel or scissors if the skin tag is irritating or cosmetically unwanted. Also known as acrochordon.