The age of majority is the age that children become adults by law. This means that they are legally in control over their own actions and decisions, and their parents are no longer responsible for them. When used this way, the word "majority" means having the full number of years to be an adult. The opposite is "minority", which means being a minor or child. The law in a given place may never actually use the words "age of majority" when deciding when people become adults. The age of majority is a legally fixed age and idea of adulthood which is different in different places. It may not match the actual maturity of a person's body or mind. The age of majority is 18 in the vast majority of jurisdictions, but ages as low as 15 and as high as 21 exist in some. 