What does "family" mean?

Many of the older girls in the middle school have read Lock and Key by Sarah Dessen, so I decided to check it out. Ruby is 17, and after her alcoholic mother deserts her, she's sent to live with her sister Cora, whom she hasn't seen in ten years. Ruby's life was poor and rough, and she has a hard time getting used to the nice home and fancy school that she's moving to. She's also been so self-reliant for so long that she's determined not to have to depend on anyone. The characters in the story are great: Nate, the way cute neighbor boy with dark secrets of his own; Jamie, Cora's likable husband and founder of a popular social networking site (think Facebook); Harriet, the hyper owner of a jewelry store at the mall who hires Ruby to help out. The author's books tend to be formulaic, but sometimes that's alright. If you like to read about a strong girl making her way through a tough situation - and it's okay for a little romance to be thrown in - you should check this one out, too.