Source : Webster's Revised Unabridged Dictionary (1913)

Labdanum \Lab"da*num\, n. (Bot.)
   See {Ladanum}.

Source : WordNet®

labdanum
     n 1: a dark brown to greenish oleoresin that has a fragrant odor
          and is used as a fixative in perfumes; obtained as a
          juice from certain rockroses [syn: {gum labdanum}]
     2: a soft blackish-brown resinous exudate from various
        rockroses used in perfumes especially as a fixative [syn:
        {ladanum}]