\Lad"a*num\, n. [L. ladanum, ledanum, Gr. la`danon,
lh`danon, fr. lh^don name of a shrub, mastic; cf. Per.
l[=a]dan, l[=a]den. Cf. {Laudanum}.]
A gum resin gathered from certain Oriental species of
{Cistus}. It has a pungent odor and is chiefly used in making
plasters, and for fumigation. [Written also {labdanum}.]