Arba had been the father of Anak

This is background information about the name of the man who founded the city of Kiriath Arba. (See: rc://en/ta/man/translate/writing-background)

Anak

An area of land with natural elevations, smaller than mountains.

An area covered with grass or plants suitable for the grazing of livestock or cattle.

Areas of open land, usually, planted with crops, belonging to and surrounding the city.

Small communities, usually smaller than a town.