The term custody refers to the physical possession or keeping of something or someone.
Child custody and guardianship are legal terms which are sometimes used to describe the legal and practical relationship between a parent and his or her child, such as the right of the parent to make decisions for the child, and the parent's duty to care for the child.
A child is usually in his or her parent's custody, but can also be put in somebody else's custody, e.g. an uncle or aunt's home, a boarding school, a summer camp, a boot camp, a reformatory or a prison. This may be for a duration of hours, days, weeks, months or years, depending on the situation.