National service is a system of either compulsory or voluntary government service, usually military service. Conscription is compulsory national service. The term national service comes from the National Service (Armed Forces) Act 1939. Voluntary enrollments at the US Peace Corps and AmeriCorps are also known as national service. Many young people spent one or more years in such programmes. Compulsory military service typically requires all male citizens to enroll for one or two years, usually at age 18 (later for university-level students), while Voluntary national service requires only three months of basic military training. The US equivalent is Selective Service.