(Heb. shittah, the thorny), is without doubt correctly referred to some species of Acacia, of which three or four kinds occur in the Bible lands. The woof of this tree--perhaps the Acacia seyal is more definitely signified--was extensively employed in the construction of the tabernacle. See Exod 25,26,36,37,38. (This tree is sometimes three or four feet in diameter (Tristram). The wood is close-grained and hard, of a fine orange-brown color, and admirably adapted to cabinet work: ED.) The A. seyal is very common in some parts of the peninsula of Sinai. It yields the well-known substance called gum arabic, which is obtained by incisions in the bark, but it is impossible to say whether the ancient Jews were acquainted with its use, and you can find more about that here on st-takla.org on other commentaries and dictionary entries. From the tangled thicket into which the stem of this tree expands, Stanley well remarks that hence is to be traced the use of the plural form of the Heb. noun shittim, the singular number occurring once only in the Bible. This acacia must not be confounded with the tree (Robinia pseudo-acacia) popularly known by this name in England, which is a North American plant, and belongs to a different genus and suborder. The true acacias belong to the order Leguminosae, sub-order Mimoseae.
Main reference: Smith's Bible Dictionary (1860s)
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