Easton's Bible Dictionary
(Hebrews lebonah; Gr. libanos, i.e., "white"), an odorous resin imported from Arabia (Isaiah 60:6; Jeremiah 6:20), yet also growing in Palestine (Cant. 4:14). It was one of the ingredients in the perfume of the sanctuary (Exodus 30:34), and was used as an accompaniment of the meat-offering (Leviticus 2:1, 16; 6:15; 24:7). When burnt it emitted a fragrant odour, and hence the incense became a symbol of the Divine name (Malachi 1:11; Cant. 1:3) and an emblem of prayer (Psalm 141:2; Luke 1:10; Revelation 5:8; 8:3).
This frankincense, or olibanum, used by the Jews in the temple services is not to be confounded with the frankincense of modern commerce, which is an exudation of the Norway spruce fir, the Pinus abies. It was probably a resin from the Indian tree known to botanists by the name of Boswellia serrata or thurifera, which grows to the height of forty feet.
Noah Webster's New International Dictionary of the English Language
(n.) A fragrant, aromatic resin, or gum resin, from trees the genus Boswellia, 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.