National service is a common name for compulsory government service (usually military service, also known as conscription). The term became standard British usage after the National Service (Armed Forces) Act 1939 and has been applied to such voluntary enrolments as the US Peace Corps. Many young people spent one or more years in such programmes. Compulsory military service typically requires all male citizens to enrol for one or two years, usually at age 18 (later for college-level students.) The US equivalent is Selective Service.