lab·da·num (lāb'də-nəm) n. A resin of certain Old World plants of the genus Cistus, yielding a fragrant essential oil used in flavorings and perfumes.
[Middle English, from Medieval Latin lapdanum, labdanum, alteration of Latin lādanum, from Greek lēdanon, lādanon, from lēdon, *lādon, rockrose, of Semitic origin; akin to Akkadian ladinnu, ladunu, an aromatic.]