From BiblePortal Wikipedia

Webster's Dictionary [1]

(n.) 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.

Hastings' Dictionary of the Bible [2]

Ladanum . See Myrrh.

International Standard Bible Encyclopedia [3]

lad´a - num ( לט , lōṭ ):   Genesis 37:25 the Revised Version margin; elsewhere Myrrh (which see).