Definition - What does Guardian mean?
A guardian is one who is legally responsible for another person. Guardians are entrusted with taking care of their charges, and watching over their property and their rights. People who require guardians are usually children, or others who are deemed incapable to handle their own affairs due to a disability or other condition.
Justipedia explains Guardian
An example of a guardian would be a father of a daughter who is only 12 years old. In this circumstance, the daughter is consider a minor, and not an adult. So, the father has the legal power to manage her affairs and rights. Children are required to have legal guardians because they are deemed unfit to be responsible for themselves due to underdevelopment. However, this changes once the child reaches 18 years of age, unless there is a specific reason, such as a disability that could limit their independence.