Lewis & Short

plaustrārĭus (plostr-), a, um, adj. [plaustrum, plostrum],

  1. I. of or belonging to a wagon, wagon-: asini, Cato, R. R. 11, 1: juga duo, id. ib. 2.
  2. II. Subst.: plau-strārĭus (plostr-), ii, m.
    1. A. A wagon-maker, wheelwright: plaustrariorum vectigal, Lampr. Alex. Sev. 24.
    2. B. A wagon-driver, wagoner: si Aquiliae actione plaustrarium (al. plostrarium) teneri placet, Dig. 9, 2, 27 fin.