וּפִֽילַגְשׁוֹ֙ אֲשֶׁ֣ר בִּשְׁכֶ֔ם יָֽלְדָה־לּ֥וֹ גַם־הִ֖יא בֵּ֑ן וַיָּ֥שֶׂם אֶת־שְׁמ֖וֹ אֲבִימֶֽלֶךְ׃
And his concubine that was in Shechem, she also bore him a son, and he called his name Abimelech.
Read midrashic interpretation of Judges 8:31: and classical rabbinic exegesis.