There are several synonyms for the word "stepmum" that can be used to describe a woman who is married to one's father but is not their biological mother. These include "stepmother," "bonus mom," "bonus mother," "blended family mother," "second mother," and "step-parent." Each of these words carries a slightly different connotation or emphasis. "Bonus mom" and "bonus mother" suggest that the woman is an addition to the family and brings something special to the role. "Blended family mother" emphasizes the bringing together of two families into one. "Second mother" suggests that the woman is a close and important figure in the child's life.