Lewis & Short

nātālīcĭus, -tĭus, a, um, adj. [1. natalis],

  1. I. of or belonging to the hour or day of one’s birth, birthday, natal (class.): qui haec Chaldaeorum natalicia praedicta defendunt, a casting of nativities, Cic. Div. 2, 42, 89: sidera, id. ib. 2, 43, 91: dapes, Mart. 7, 86, 1: lardum, Juv. 11, 84: sinciput, Petr. 136; Pers. 1, 16: dies natalicius, Vulg. Gen. 40, 20.
    Hence,
  2. II. Subst.
    1. A. nātālīcĭ-um (-tĭum), ii, n., a birthday present: aliquid natalicii titulo tibi mittere, Censor. de Die Nat. 1.
    2. B. nātālīcĭa, ae, f. (sc. cena), a birthday entertainment: hodie non descendit Antonius. Cur? Dat nataliciam in hortis, Cic. Phil. 2, 6, 15 (so acc. to Cod Vat.; others natalicia, as n. plur.).