EASTON’S BIBLE DICTIONARY (1897 EDITION)
Atad – buckthorn, a place where Joseph and his brethren, when on their way from Egypt to Hebron with the remains of their father Jacob, made for seven days a “great and very sore lamentation.”
On this account the Canaanites called it “Abel-mizraim” (Gen. 50:10, 11).
It was probably near Hebron.
The word is rendered “bramble” in Judg. 9:14, 15, and “thorns” in Ps. 58:9.