An adult may mean different things. In law and social norms, an adult is a human who has reached the age of majority. The age of majority is the age at which an individual will be legally considered an adult. That age varies: in most countries, an adult is a person who is 18 years old or older. Once someone is adult, they no longer have to take directions from a parent or guardian but can make decisions for themselves, and "be held responsible for their own actions". Legal penalties for crimes are different before and after the age of majority. 