Lewis & Short

1. cursor, ōris, m. [cursito],

  1. I. a runner, and partic.,
    1. A. A runner in a race, racer, Lucr. 2, 78; Cic. Tusc. 2, 23, 56; id. Div. 2, 70, 144; also a competitor in a chariot-race: ut cupidi cursor frena retentat equi, Ov. P. 3, 9, 26.
    2. B. A courier, post (mostly postAug.), Nep. Milt. 4, 3 (transl. of the Gr. ἡμεροδρόμος); Plin. 2, 71, 73, § 181; Plin. Ep. 7, 12 fin.; Suet. Ner. 49; Mart. 3, 100, 1 al.
    3. C. A slave who ran before the chariot of a grandee, a forerunner (post-Aug.), Sen. Ep. 87, 9; 123, 7; Suet. Ner. 30; Mart. 3, 47, 14.
  2. II. Trop.: cursor iambus, Rufin. Rhet. p. 355 Capperon.