stepparent adoption

Definition from Nolo’s Plain-English Law Dictionary

The formal, legal adoption of a child by a stepparent who is married to a legal parent or in a marriage-equivalent relationship like a domestic partnership or civil union. Most states have special provisions making stepparent adoptions relatively easy if the child's noncustodial parent gives consent, is dead or missing, or has abandoned the child.

Definition provided by Nolo’s Plain-English Law Dictionary.