Mess dress is the military

Military

A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...

 term for the formal evening dress

Evening dress

Evening dress may refer to:* White tie, the most formal civilian dress code in Western fashion* Black tie, a semi-formal dress code for evening events and social functions in Western fashion...

 worn in the mess

Mess

A mess is the place where military personnel socialise, eat, and live. In some societies this military usage has extended to other disciplined services eateries such as civilian fire fighting and police forces. The root of mess is the Old French mes, "portion of food" A mess (also called a...

 or at other formal occasions. It is also known as mess uniform and mess kit. This style of military dress is largely restricted to the British, Commonwealth of Nations

Commonwealth of Nations

The Commonwealth of Nations, normally referred to as the Commonwealth and formerly known as the British Commonwealth, is an intergovernmental organisation of fifty-four independent member states...

 and United States armed forces

United States armed forces

The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...

; although the Imperial German and other navies adopted their own versions during the late nineteenth century, influenced by the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

.
The Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 and some other navies distinguish between mess dress, which is now the equivalent of civilian white tie

White tie

White tie is the most formal evening dress code in Western fashion. It is worn to ceremonial occasions such as state dinners in some countries, as well as to very formal balls and evening weddings...

, and mess undress, which is the equivalent of black tie

Black tie

Black tie is a dress code for evening events and social functions. For a man, the main component is a usually black jacket, known as a dinner jacket or tuxedo...

.

Before 1939, there were three forms of evening dress:

• Ball dress (no.