Lewis & Short

cŏ-aequālis, e, adj., of equal age, coeval (post-Aug.): sinciput, Petr. 136, 1.
Subst., a comrade, companion in age, Just. 23, 4, 9; Inscr. Orell. 4407 al.
Transf., of geese, Col. 8, 14, 8.