Lewis & Short

2. Dĕcĭmus, i, m., Dĕcĭma, ae, f., proper names.

  1. I. Decimus, a Roman praenomen, abbrev. D. In the gens Claudia it was given only to patricians; but among the Junii and Laelii to plebeians also; cf. Varr. L. L. 9, § 61 Müll.
    Hence, Dĕcĭmiānus, a, um, adj., named for Decimus: pirus, Plin. 15, 15, 16, § 54.
  2. II. Decima, the goddess that presides over accouchements, a partus tempestivi tempore, Varr. and Caesel. ap. Gell. 3, 16, 10 sq.; cf. also Tert. Anim. 37; id. adv. Val. 32.