Know how to use "fewer" and "less"? Find out.
1540s, from Latin acacia, from Greek akakia "thorny Egyptian tree," perhaps related to Greek ake "point, thorn," from PIE root *ak- "sharp" (see acrid). Or perhaps a Hellenization of some Egyptian word. From late 14c. in English as the name of a type of gum used as an astringent, etc.
(Heb. shittim) Ex. 25:5, R.V. probably the Acacia seyal (the gum-arabic tree); called the "shittah" tree (Isa. 41:19). Its wood is called shittim wood (Ex. 26:15,26; 25:10,13,23,28, etc.). This species (A. seyal) is like the hawthorn, a gnarled and thorny tree. It yields the gum-arabic of commerce. It is found in abundance in the Sinaitic peninsula.