A fragrant, aromatic resin, or gum resin, burned as
   an incense in religious rites or for medicinal fumigation. The best
   kinds now come from East Indian trees, of the genus Boswellia; a
   commoner sort, from the Norway spruce (Abies excelsa) and other
   coniferous trees. The frankincense of the ancient Jews is still
   unidentified.