The Collaborative International Dictionary of English v.0.48:
Clavus \Cla"vus\, n. [L., a nail.] A callous growth, esp. one the foot; a corn. [1913 Webster]WordNet (r) 3.0 (2006):
clavus n 1: a hard thickening of the skin (especially on the top or sides of the toes) caused by the pressure of ill-fitting shoes [syn: corn, clavus]