Lewis & Short

Calvēna, ae, m. [calvus], a nickname of the bald-headed Matius, a friend of Cœsar, Cic. Att. 14, 5, 1; 14, 9, 3; 16, 11, 1 (so id. ib. 14, 2, 2, the name Madarus = μαδαρός, bald).