Lewis & Short

† ŏpŏbalsămum, i, n., = ὀποβάλσαμον,

  1. I. the juice of the balsam-tree, opobalsam, balsam, balm, Stat. S. 3, 2, 141; Just. 36, 3, 4; Plin. 37, 13, 78, § 204.
    Used for embalming bodies, Inscr. Grut. 692, 10.
  2. II. Hence, in gen., perfume: hirsuto spirant opobalsama collo Quae tibi, Juv. 2, 41.