Conscription is the state-mandated enlistment of people in a national service, mainly a military service. Conscription dates back to antiquity and it continues in some countries to the present day under various names. The modern system of near-universal national conscription for young men dates to the French Revolution in the 1790s, where it became the basis of a very large and powerful military. Most European nations later copied the system in peacetime, so that men at a certain age would serve 1 to 8 years on active duty and then transfer to the reserve force.

Military service is service by an individual or group in an army or other militia, air forces, and naval forces, whether as a chosen job (volunteer) or as a result of an involuntary draft (conscription).