An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age. In human context, the term has other subordinate meanings associated with social and legal concepts; for example, a legal adult is a legal concept for a person who has attained the age of majority and is therefore regarded as independent, self-sufficient, and (contrast with "minor"). Adulthood can be defined in terms of physiology, psychological adult development, law, personal character, or social status. These different aspects of adulthood are often inconsistent and contradictory. A person may be biologically an adult, and have adult behavior but still be treated as a child if they are under the legal age of majority. Conversely one may legally be an adult but possess none of the maturity and responsibility that may define adult character.

The ICM Registry who operates the registry for the sponsored top-level domain (sTLD) .XXX which is intended for the adult entertainment industry has announced a further 3 applications to ICANN for 3 new adult-themed TLDs, .ADULT, .SEX and .PORN.

ADULT. is an American band from Detroit, Michigan that integrates vocals with drum machines, analog synths and electronic/punk elements. While popular in their home city of Detroit, they are also very popular in Germany and the United Kingdom.

Pornographic magazines, sometimes known as adult, sex or top-shelf magazines, are magazines that contain content of a sexual nature. Publications of this kind generally contain images of attractive naked models, as is the case in softcore pornography, and, in the usual case of hardcore pornography, depictions of masturbation, oral or anal sex, and intercourse.