Lewis & Short

lĭgustrum, i, n.,

  1. I. a plant, privet: alba ligustra cadunt, Verg. E. 2, 18: candidior folio nivei, Galatea, ligustri, Ov. M. 13, 789: loto candidior puella cygno, argento, nive, lilio, ligustro, Mart. 1, 116, 3.
  2. II. A plant, otherwise unknown, which, acc. to Pliny, was held by some to be the cyprus, Plin. 12, 24, 55, § 109; 24, 10, 45, § 74; 16, 18, 31, § 77.
    To this perhaps may be referred ligustrum nigrum, Col. 10, 300.