The time of life at which a person acquires full capacity to make his or her own contracts and deeds and to transact business or to enter into some particular contract or relation, such as marriage.

In most states a minor attains legal age at eighteen, although for certain acts, such as consuming alcoholic beverages, the age might be higher; for others, such as driving, the age might be lower. Legal age is synonymous with age of consent or age of majority.