Lewis & Short

Cerretāni, ōrum, m., an Iberian people of Hispania Tarraconensis, among the Pyrenees, Plin. 3, 3, 4, § 22; Sil. 3, 357.
Hence, Cerretānus, a, um, of the Cerretani: perna, Mart. 13, 54, 1.