Biologically, an adult is a human or other organism that has reached sexual maturity.In human context, the term adult additionally has meanings associated with social and legal concepts. In contrast to a "minor", a legal adult is a person who has attained the age of majority and is therefore regarded as independent, self-sufficient, and responsible.
Adult Law and Legal Definition An adult is a person who has attained the age of majority. The age of majority is the legally defined age at which a person is considered an adult, with all the attendant rights and responsibilities of adulthood.
The age of majority, on the other hand, is legal recognition that one has grown into an adult.  Age of majority pertains solely to the acquisition of the legal control over one's person, decisions and actions, and the correlative termination of the legal authority of the parents (or guardian(s), in lieu of parent(s)) over the child’s ...
Being of legal voting age, 18, is considered legal adulthood in the United States. Most states have set 21 as the legal age for drinking alcohol. Becoming a legal adult at 18 is not enough to buy alcohol, which requires someone to be 21.
Foreign Service children become adults at age 18 in the United States. It is important, as the parent of a child in the Foreign Service, to know at what age some of the regulations change. Employees should contact their Career Development Officer (CDO) regarding their child(ren) being on orders.
This compares to US figures where minimum age ranges from 15-16, and generally, one must have permission from parents to work prior to being 18 and being considered an adult. Age of marriage, which is often considered the time at which one becomes an adult in certain countries, also shows great variance.
adult a person who has attained the age of legal majority. ADULT, in the civil law. An infant who, if a boy, has attained his full age of fourteen years, and if a girl, her full age of twelve. Domat, Liv. Prel. t. 2, s. 2, n. 8. In the common law an adult is considered one of full age. 1 Swanst. R. 553.
The age of adulthood is a transition in the U.S., with different rights being given at different ages. Not all of those rights occur at 18. Generally the Age of Majority would be considered the age when a person is an adult.
New York officials proposed Monday to raise the legal age to buy cigarettes from 18 to 21. ... the age of majority—the age at which a person has the legal rights and responsibilities of an adult ...
Well the legal age of being and adult varies from country to country. However it is always around 18. Now coming to your answer as to why is one legally considered an adult at 18. It is probably because this is the age when people start becoming self dependent and start making wise decision.