The definition of family in the u. s. has been stable since the colonial era

Depending on if you're asking if this is true or false then it is highly false because of the changes in society and what an individual believes is in their own definition a family. Families aren't always the mother and father and their children-over the years families have evolved as society has changed. Families have gone from a two parent household to a single parent household when either the father or mother can be the superior figure of the house. (Hope this helps some ^^)