Lewis & Short

prōtēlum, i, n.

  1. I. A row of oxen, etc., harnessed together for draught, a team: protelo trini boves unum aratrum ducent, Cato ap. Non. 363, 10; Lucil. ib. 363, 7 and 8: boum, Plin. 9, 15, 17, § 45: bina ternaque, id. 18, 18, 48, § 173; cf.: protelum, ἔξαμπρον, Gloss. Philox.
  2. II. Transf., a line, row, succession (ante-class. and poet.): protelo plagarum continuato, Lucr. 2, 531; 4, 190.