Define, please

I was watching a show about how the media goes all out when a white child goes missing, but does not do the same for missing black children. Chris Cuomo is advocating for increased coverage in these cases, and had several parents of missing black children as guests on the show. One mother said she didn't find out her seven-year-old daughter was missing until the end of the school day, and it turned out the child had not been in school all day, and had not been contacted by the school. The last time she saw her child was when her stepfather walked her to school, just across the street. Such a sad story. Which brings to mind, what is the definition of a stepfather? Just asking.