The term has been used to describe veterans who were in the armed forces of South Vietnam, the United States armed forces, and countries allied to them, whether or not they were actually stationed in Vietnam during their service. However, the more common usage distinguishes between those who served "in country" and those who did not actually serve in Vietnam by referring to the "in country" veterans as "Vietnam veterans" and the others as "Vietnam-era veterans". The U.S. government officially refers to all as "Vietnam-era veterans".