Heb. hedek (Proverbs 15:19), rendered "brier" in Micah 7:4. Some thorny plant, of the Solanum family, suitable for hedges. This is probably the so-called "apple of Sodom," which grows very abundantly in the Jordan valley. "It is a shrubby plant, from 3 to 5 feet high, with very branching stems, thickly clad with spines, like those of the English brier, with leaves very large and woolly on the under side, and thorny on the midriff."
Heb. na'atzutz (Isaiah 7:19; 55:13). This word has been interpreted as denoting the Zizyphus spina Christi, or the jujube-tree. It is supposed by some that the crown of thorns placed in wanton cruelty by the Roman soldiers on our Saviour's brow before his crucifixion was plaited of branches of this tree. It overruns a great part of the Jordan valley. It is sometimes called the lotus-tree. "The thorns are long and sharp and recurved, and often create a festering wound." It often grows to a great size. (See CROWN OF THORNS .)
Heb. atad (Psalms 58:9) is rendered in the LXX. and Vulgate by Rhamnus, or Lycium Europoeum, a thorny shrub, which is common all over Palestine. From its resemblance to the box it is frequently called the box-thorn.
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Thorn'". "Easton's Bible Dictionary". <http://classic.studylight.org/dic/ebd/view.cgi?number=T3642>. 1897.