an army where military service is the basic occupation and activity of all personnel.
In the history of armed forces, professional armies existed in ancient Greece, Rome, and other states. In the 14th through 18th centuries, Western European countries, such as France, Italy, Germany, Spain, and the Netherlands, had mercenary armies of professional soldiers who were at first called up for temporary periods and later became members of standing armies. In Russia the regular army of the 18th century and first half of the 19th, which was composed of recruits serving long terms, was in fact a professional army. Since the 19th century, after most European countries introduced universal military service, the armed forces have been raised by drafting citizens for a relatively short term of service. In the modern armed forces, Great Britain, the USA, and several other states have professional armies (wholly or partly).