A guardian is someone legally responsible for taking care of another person, usually a child whose parents cannot care for them. When parents die or cannot fulfill their duties, a court may appoint a guardian to make important decisions about the child's life: where they live, what school they attend, and how their money is managed.

Guardians can be relatives like grandparents, aunts, or uncles, but they can also be family friends or professionals appointed by the court. Unlike adoptive parents, guardians don't permanently replace the parents. The arrangement can change if circumstances improve. A guardian has serious responsibilities: providing food, shelter, education, and making medical decisions, just as a parent would.

The word also appears in broader contexts. Museums have guardians who protect valuable artwork. A guardian angel is a spiritual protector in religious traditions. When someone acts as a guardian of an idea or tradition, they work to preserve and protect it.