Frankincense, also known as olibanum (/oʊˈlɪbənəm/),[1] is an aromatic resin used in incense and perfumes, obtained from trees of the genus Boswellia in the family Burseraceae. The word is from Old French franc encens ('high-quality incense').[2] There are several species of Boswellia that produce true frankincense:[3] Boswellia sacra (syn. B. bhaw-dajiana, syn. B. carteri), B. frereana, B. serrata (B. thurifera, Indian frankincense), and B. papyrifera. Resin from each is available in various grades, which depends on the time of harvesting. The resin is hand-sorted for quality.
OED1933_Frankincense
was invoked but never defined (see the help page).