CLAVUS, in medicine and surgery, is used in several significations: 1. Clavus hytericus, is a shooting pain in the head, between the pericranium and cranium, which affects such as have the green-sickness. 2. Clavus oculorum, according to Celus, is a callous tubercle on the white of the eye, taking its denomination from its figure. 3. Clavus imports indurated tubercles of the uterus. 4. It also imports a churgical instrument of gold, mentioned by Amatus Lusitanus, designed to be introduced into an ulcerated palate, for the better articulation of the voice. And, 5. It signifies a callus, or corn on the foot.