Bonus mom - Idioms by The Free Dictionary
An alternative to the title "step-mom," which is a female caregiver of a child who assumed the parental role through marriage to one of the child's original (usually biological) parents. Most commonly, a step-mom is the second wife of a child's biological father. I live with my mom during the week and then visit my dad and bonus mom every other weekend.
References in periodicals archive
Smith called herself a "bonus mom
" to her fiance's daughter and loved taking her to his softball games and having game nights at home, Dedmon said.
"My Bonus Mom
!: Taking the Step Out of Stepmom" is a great adjustment handbook for children of divorced and blended families.