Abimelech in the Bible Encyclopedia - ISBE

a-bim'-e-lek ('abhimelekh, "father of a king"): A name borne by five Old Testament persons. (1) The name of two kings of Philistia; the first was a contemporary of Abraham, the second, probably son of the former, was king in the days of Isaac. It is quite possible that Abimelech was the royal title rather than the personal name, since in the title of Ps 34 we find it applied to the king of Gath, elsewhere known by his personal name, Achish (1 Sam 27:2,3). Shortly after the destruction of Sodom Abraham journeyed with his herds and flocks into the extreme Southeast country of Israel (Gen 20). While sojourning at Gerar, the city of Abimelech, king of the Philistine country, he made believe that Sarah was his sister (Gen 20:2), and Abimelech took her, intending to make her one of his wives. But God rebuked him in a dream, besides sending barrenness on the women of his household (Gen 20:3,17). After Abimelech had reproved Abraham most justly for the deception, he dealt generously with him, loading him with presents and granting him the liberty of the land (Gen 20:14,15). When contention had arisen between the servants of the two men over the wells of water the two men made a covenant at a well, which took its name, Beersheba, from this fact of covenantmaking (Gen 21:31,32)...

Link: https://bible-history.com/isbe/A/ABIMELECH/