Definition - What does Family Law mean?
Family law is the section of law that encompasses all statutes, rulings, and federal and state constitutional provisions that deal with the family. This can include laws about divorce, adoption, marriage, etc.
Family laws can vary significantly from state to state.
Justipedia explains Family Law
Family law can determine things like spousal support, child support, whether or not a person can adopt a child, whether or not a divorced parent will have custody or partial custody of a child and so forth.
Family law is just one of many areas of law; there are attorneys who specialize in this field, e.g. divorce lawyers.