bonus family
n.— «The two coined a phrase to replace “stepfamilies,” a word they say often has a negative connotation. They decided on “bonus families,” because a bonus is a reward for a job well done. And, they say, “it’s hard work to be a good bonus parent.”» —“Divorce etiquette? These women wrote the book” by Leslie Garcia Dallas Morning News (Texas) Jan. 11, 2005. (source: Double-Tongued Dictionary)