From BiblePortal Wikipedia

Bridgeway Bible Dictionary [1]

Anak was a Canaanite whose descendants (called Anakim, plural of Anak) were giants. They lived in the south of Canaan in the hill country around Hebron. Because of the great size and fearsome appearance of the Anakim, the Israelites saw them as an obstacle to the conquest of Canaan. Only Joshua and Caleb believed Israel could conquer them ( Numbers 13:22-33;  Deuteronomy 9:2).

Joshua and Caleb were, in fact, the ones who eventually led the attack on the Anakim. Most of the Anakim were slaughtered, the only ones who managed to escape being those who found refuge in the Philistine towns of Gaza, Gath and Ashdod ( Joshua 11:21-22;  Joshua 14:6-15). Gath remained the home of giants for several centuries ( 1 Samuel 17:4;  2 Samuel 21:18-22).

Watson's Biblical & Theological Dictionary [2]

ANAKIM, famous giants in Palestine. Anak, father of the Anakim, was son of Arba, who gave his name to Kirjath-Arba, or Hebron. Anak had three sons, Sheshai, Ahiman, and Talmai, whose descendants were terrible for their fierceness and stature. The Hebrew spies reported that in comparison of those monstrous men, they themselves were but grasshoppers. Some have thought that the name Phoenician, given to the Canaanites, and particularly to the Sidonians, was originally from Bene- Anak, sons of Anak. Caleb, assisted by the tribe of Judah, took Kirjath- Arba, and destroyed the Anakim, A.M. 2559.   Joshua 15:14;  Judges 1:20 .

Easton's Bible Dictionary [3]

 Joshua 15:13 21:11 Anok

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [4]

(Heb., Anak', עֲנָק [in  Joshua 21:11, Anok', עֲנוֹק ] , Long-Necked, i.e. a Giant; Sept. Ε᾿Νάκ ) , the son of Arba, who founded Kirjath-Arba (afterward Hebron), the progenitor of a race of giants called ANAKIN (See Anakin) ( Joshua 15:13). B.C. ante 1658.