An alternative to the title "step-son," which is a male child of a step-parent who assumed the parental role through marriage to one of the child's original (usually biological) parents. Most commonly, the step-parent is the second spouse of one of the child's biological parents. My bonus son comes to visit his father and me every other weekend.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.