Lewis & Short

ŏlĕārĭus, a, um, adj. [oleum],

  1. I. of or belonging to oil, oil- (class.): cella vinaria, olearia, Cato, R. R. 3; Cic. Sen. 16, 56: dolia, Plin. 15, 8, 8, § 33: mercatores, Dig. 50, 4, 5.
  2. II. Subst.: ŏlĕārĭus, ii, m., an oilgrinder or oil-seller: in velabro olearii, Plaut. Capt. 3, 1, 29: diligentes, Col. 12, 50, 13.