'Mother's' in the Bible

Abimelech the son of Jerubbaal went to Shechem to his mother's brothers, and spoke with them, and with all the family of the house of his mother's father, saying,

His mother's brothers spoke of him in the ears of all the men of Shechem all these words: and their hearts inclined to follow Abimelech; for they said, "He is our brother."

He told her all his heart, and said to her, "No razor has ever come on my head; for I have been a Nazirite to God from my mother's womb. If I am shaved, then my strength will go from me, and I will become weak, and be like any other man."