In the criminal justice system in some places, "minor" is not entirely consistent, as a minor may be tried and punished for a crime either as a "juvenile" or, usually only for "extremely serious crimes" such as murder and/or theft, as an "adult".
Minor may also be used in contexts that are unconnected to the overall age of majority.
For example, the drinking age in the United States is usually 21, and younger people are sometimes called minors in the context of alcohol law, even if they are at least 18.
Driving certain large vehicles, acting as personal license holder for licensed premises, and adopting a child are only permitted after the age of 21.
The minimum age to drive a HGV1 vehicle was reduced to 18.
However, certain vehicles, e.g., steamrollers, require that someone be 21 years of age to obtain an operating license.