Lewis & Short

Caeso (Kaeso, v. the letter K), ōnis, m. [a caeso matris utero dictus, Plin. 7, 9, 7, § 47; cf. Paul. ex Fest. p. 57 Müll.; Isid. Orig. 9, 3, 12, and v. Caesar init.], a Roman cognomen in the gens Fabia, Liv. 2, 43, 2; 2, 48, 3 and 4; 3, 11, 6 sq. et saep.