Anakim

(long-necked), a race of giants, descendants of Arba, (Joshua 15:13; 21:11) dwelling in the southern part of Canaan, and particularly at Hebron, which from their progenitor received the name of "city of Arba." Anak was the name of the race rather than that of an individual. (Joshua 14:15) The race appears to have been divided into three tribes or families, bearing the names Sheshai, Ahiman and Talmai, and you can find more about that here on st-takla.org on other commentaries and dictionary entries. Though the war-like appearance of the Anakim had struck the Israelites with terror in the time of Moses, (Numbers 13:28; 9:2) they were nevertheless dispossessed by Joshua, (Joshua 11:21,22) and their chief city, Hebron, became the possession of Caleb. (Joshua 15:14; Judges 1:20) After this time they vanish from history.