One of the defining features of a professional military is a strict and sometimes elaborate code of courtesy.

Military courtesy is an extension and a formalization of courtesies practiced in a culture's everyday life. These courtesies are intended to reinforce discipline and the chain of command, defining how soldiers will treat their superiors and vice versa. They are also thought to enhance esprit de corps.

Some military courtesies include proper forms of address ("Sir", "Ma'am", "Mister") and when each should be used; the salute, and the related concept of standing at attention; proper wear of military headgear; obeisance; and the rules for behavior in various ceremonies.

Reference

• Swartz, Oretha. Service Etiquette, Naval Institute Press, Annapolis, MD.

  (covers customs of the United States Military)