Full dress uniform in the context of "Battledress"

The Pontifical Swiss Guard, also known as the Papal Swiss Guard or simply Swiss Guard, is an armed forces, guard of honour, and protective security unit, maintained by the Holy See to protect the Pope and the Apostolic Palace within the territory of the Vatican City State. Established in 1506 under Pope Julius II, it is among the oldest military units in continuous operation and is sometimes called "the world's smallest army".

The Swiss Guard is recognised by its Renaissance-era dress uniform, consisting of a tunic striped in red, dark blue, and yellow; high plumed helmet; and traditional weapons such as the halberd. Guardsmen perform their protective duties in functional attire and with modern firearms. Since the assassination attempt on Pope John Paul II in 1981, the Guard has placed greater emphasis on its nonceremonial roles and has sought more training in anti-irregular military counterintelligence, commando-style raids, counter-sniper tactics, counterterrorism, close-quarters battle, defusing and disposal of bombs, executive protection, hostage rescue, human intelligence, medical evacuation, reconnaissance, tactical driving, tactical medical services, and tactical fast shooting by small arms.

Formal wear or full dress is the Western dress code category applicable for the most formal occasions, such as weddings, christenings, confirmations, funerals, Easter and Christmas traditions, in addition to certain state dinners, audiences, balls, and horse racing events. When formal dress is required, generally permitted alternatives include the most formal versions of ceremonial dresses (including court dresses, diplomatic uniforms and academic dresses), full dress uniforms, religious clothing, national costumes, and most rarely frock coats (which preceded morning coat as default formal day wear 1820s-1920s). In addition, formal wear is often properly worn when displaying official full size orders and medals.

The protocol specifying men's traditional formal wear has remained virtually unchanged since the early 20th century. Despite decline following the counterculture of the 1960s, it remains observed in formal settings influenced by Western culture: notably around Europe, the Americas, South Africa, Australia, as well as Japan. For women, although fundamental customs for formal ball gowns (and wedding gowns) likewise apply, changes in fashion have been more dynamic. Traditional formal headgear for men is the top hat, and for women picture hats etc. of a range of interpretations. Shoes for men are dress shoes, dress boots or pumps, and for women heeled dress pumps. In western countries, a "formal" or white tie dress code typically means tailcoats for men and evening dresses for women. The most formal dress for women is a full-length ball or evening gown with evening gloves. Some white tie functions also request that the women wear long gloves past the elbow.

A uniform is a variety of costume worn by members of an organization while usually participating in that organization's activity. Modern uniforms are most often worn by armed forces and paramilitary organizations such as police, emergency services, security guards, in some workplaces and schools, and by inmates in prisons. In some countries, some other officials also wear uniforms in their duties; such is the case of the Commissioned Corps of the United States Public Health Service or the French prefects. For some organizations, such as police, it may be illegal for non-members to wear the uniform.

Service dress uniform is the informal type of uniform used by military, police, fire and other public uniformed services for everyday office, barracks and non-field duty purposes and sometimes for ceremonial occasions. It frequently consists of a jacket, trousers, dress shirt, and neck tie, along with orders, medals, and insignia. Design may depend on regiment or service branch, e.g. army, navy, air force, marines, etc. In Western dress codes, a service dress uniform is a permitted supplementary alternative equivalent to the civilian suit—sometimes collectively called undress or "dress clothes". As such, a service dress uniform is considered less formal than both full dress and mess dress uniforms, but more formal than combat uniforms.

Service dress uniforms were originally worn in active service in the field or at sea, but became relegated to office, barracks, and walking out dress as more practical field uniforms evolved. In some parts of some armed forces such as the British Army, service dress uniform may also be used for ceremonial occasions, gradually replacing in this role the full dress uniforms that had preceded them as field uniforms. In the United States Navy, for example, service dress uniforms are worn for official functions not rising to the level of full dress or mess dress uniforms. They are also commonly worn when travelling in official capacity, or when reporting to a command. They may be seasonal, with a white uniform worn in summer and darker versions in winter.

Mess dress uniform is the most formal (or semi-formal, depending on the country) type of evening-wear uniform used by military personnel, police personnel, and other uniformed services members. It frequently consists of a mess jacket, trousers, white dress shirt and a black bow tie, along with orders, medals, and insignia. Design may depend on regiment or service branch, e.g. army, navy, air force, marines, etc. In modern Western dress codes, mess dress uniform is the supplementary alternative equivalent to the civilian black tie for evening wear. Mess dress uniforms are typically less formal than full dress uniform, but more formal than service dress uniform.

Prior to World War II, this style of military uniform was largely restricted to the British and United States Armed Forces, although the French, German, Swedish and other navies had adopted their own versions of mess dress during the late 19th century, influenced by the British Royal Navy.