Justaucorps in the context of Suit (clothing)

A top hat (also called a high hat, or, informally, a topper) is a tall, flat-crowned hat traditionally associated with formal wear in Western dress codes, meaning white tie, morning dress, or frock coat. Traditionally made of black silk or sometimes grey, the top hat emerged in Western fashion by the end of the 18th century. Although such hats fell out of fashion through the 20th century, being almost entirely phased out by the time of the counterculture of the 1960s, it remains a formal fashion accessory. A collapsible variant of a top hat, developed in the 19th century, is known as an opera hat.

Perhaps inspired by the early modern era capotain, higher-crowned dark felt hats with wide brims emerged as a country leisurewear fashion along with the Age of Revolution around the 1770s. Around the 1780s, the justaucorps was replaced by the previously casual frocks and dress coats. With the introduction of the top hat in the early 1790s, the tricorne and bicorne hats began falling out of fashion. By the start of the 19th century, the directoire style dress coat with top hat was widely introduced as city wear for the upper and middle classes in all urban areas of the Western world. The justaucorps was replaced in all but the most formal court affairs. Around the turn of the 19th century, although for a few decades beaver hats were popular, black silk became the standard, sometimes varied by grey ones. While the dress coats were replaced by the frock coat from the 1840s as conventional formal daywear, top hats continued to be worn with frock coats as well as with what became known as formal evening wear white tie. Towards the end of the 19th century, whereas the white tie with black dress coat remained fixed, frock coats were gradually replaced by morning dress, along with top hats.

A frock coat is a formal men's coat characterised by a knee-length skirt cut all around the base just above the knee, popular during the Victorian and Edwardian periods (1830s–1910s). It is a fitted, long-sleeved coat with a centre vent at the back and some features unusual in post-Victorian dress. These include the reverse collar and lapels, where the outer edge of the lapel is often cut from a separate piece of cloth from the main body and also a high degree of waist suppression around the waistcoat, where the coat's diameter around the waist is less than around the chest. This is achieved by a high horizontal waist seam with side bodies, which are extra panels of fabric above the waist used to pull in the naturally cylindrical drape. As was usual with all coats in the 19th century, shoulder padding was rare or minimal.

In the Age of Revolution around the end of the 18th century, men abandoned the justaucorps with tricorne hats for the directoire style: dress coat with breeches or increasingly pantaloons, and top hats. However, by the 1820s, the frock coat was introduced along with full-length trousers (pants), perhaps inspired by the then casual country leisure wear frock. Early frock coats inherited the higher collars and voluminous lapels of the dress coat style at the time, and were sometimes offered in different, albeit increasingly dark, colours. Within a few years, though, plain black soon became the only established practice, and with a moderate collar. The top hat followed suit.

White tie, also called full evening dress or a dress suit, is the most formal evening Western dress code. For men, it consists of a black tail coat (alternatively referred to as a dress coat, usually by tailors) worn over a white dress shirt with a starched or piqué bib, white piqué waistcoat and the white bow tie worn around a standing wing collar. Mid or high-waisted black trousers with galon, a braid of trim consisting of two silk stripes to conceal the outer seams of the trousers, along with court shoes (British English) (pumps in American English) complete the outfit. Orders, decorations and medals in miniature may be worn. Acceptable accessories include a black top hat, white gloves, a white scarf, a pocket watch, a white pocket square, and a boutonnière. Women wear full-length ball or evening gowns with evening gloves and, optionally, tiaras, jewellery, and a small handbag.

The dress code's origins can be traced back to the end of the 18th century. New fully black-coloured justaucorps styles emerged around the Age of Revolution, notably adopted by the bourgeois third estate of the Estates General of the Kingdom of France. Increasingly following the French Revolution, high society men abandoned the richly decorated justaucorps coats for more austere cutaway dress coats in dark colours, with cuts perhaps further inspired by the frocks and riding coats of country gentlemen. Gradually replacing also breeches, lacy dress shirts and jabots with plain white dress shirts, shorter waistcoats, white cravats and pantaloons, this became known as directoire style. By the early 19th-century Regency era, dark dress tailcoats with light trousers became standard daywear, while black and white became the standard colours for evening wear. Although the directoire style was replaced for daytime by black frock coats and bowties by mid-19th century, cutaway black dress tailcoats with white bowtie has remained established for formal evening wear ever since.