n. [ L. ladanum, ledanum, Gr. la`danon, lh`danon, fr. lh^don name of a shrub, mastic; cf. Per. lādan, lāden. 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. ] [ 1913 Webster ]