Guard·i·an n.
1. One who guards, preserves, or secures; one to whom any person or thing is committed for protection, security, or preservation from injury; a warden.
2. Law One who has, or is entitled to, the custody of the person or property of an infant, a minor without living parents, or a person incapable of managing his own affairs.
Of the several species of guardians, the first are guardians by nature. -- viz., the father and (in some cases) the mother of the child. --Blackstone.
Guardian ad litem Law, a guardian appointed by a court of justice to conduct a particular suit.
Guardians of the poor, the members of a board appointed or elected to care for the relief of the poor within a township, or district.