Term used to denote Age of Consent, the age where a person is legally capable of giving consent to any sexual act. The age of consent can differ from state to state, and country to country.
In Canada, the age of consent is generally 14, provided they are not giving consent to someone in a position of authority over them, such as a doctor, priest, teacher, or babysitter, for any combination of genders, although with an exception for sodomy, where an age of 18 applies.
In the United States, age of consent varies from 14 to 18 from state to state, and can be illegal for same-sex couples.
In much of Europe, the age is around 15 or 16, although it is 13 in Spain.
Further enlightening information can be found at http://www.ageofconsent.com/