Formal attire in the context of "Court dress"

Trousers (British English), slacks, or pants in (Northern English, American, Canadian and Australian English) are an item of clothing worn from the waist to anywhere between the knees and the ankles, covering both legs separately (rather than with cloth extending across both legs as in robes, skirts, dresses and kilts).Shorts are similar to trousers, but with legs that come down only as far as the knee, but may be considerably shorter depending on the style of the garment. To distinguish them from shorts, trousers may be called "long trousers" in certain contexts such as school uniform, where tailored shorts may be called "short trousers" in the UK.

The oldest known trousers, dating to the period between the thirteenth and the tenth centuries BC, were found at the Yanghai cemetery in Turpan, Xinjiang (Tocharia), in present-day western China. Made of wool, the trousers had straight legs and wide crotches and were likely made for horseback riding. A pair of trouser-like leggings dating back to 3350 and 3105 BC were found in the Austria–Italy border worn by Ötzi. In most of Europe, trousers have been worn since ancient times and throughout the Medieval period, becoming the most common form of lower-body clothing for adult males in the modern world. Breeches were worn instead of trousers in early modern Europe by some men in higher classes of society. Distinctive formal trousers are traditionally worn with formal and semi-formal day attire. Since the mid-twentieth century, trousers have increasingly been worn by women as well.

Formal trousers, also known as formal striped trousers or colloquially spongebag trousers, are grey striped or patterned formal trousers for day attire in traditional Western dress code, primarily associated with formal morning dress or secondly its semi-formal equivalent black lounge suit. Traditionally made from heavy wool ranging from worsted, melton to partial twill weave, the pattern is most often of a muted design in stripes of black, silver, white and charcoal grey in various combinations (not to be confused with pinstripe or chalkstripe, which are formed of single thin lines spaced equally apart). In addition, formal trousers may also come in check patterns, such as houndstooth check, or plaids, although these variants are widely considered as not the most formal.

Typically, formal trousers are intended to be worn with braces with a fishtail back covered by a waistcoat, and have pleats for correct ironing result and comfort. Likewise, for traditional reasons of formality, they do not have turn-ups, since these are considered less formal.

Morning dress, also known as formal day dress, is the formal Western dress code for day attire, consisting chiefly of a morning coat, waistcoat, and formal trousers for men, and an appropriate gown for women. Men may also wear a popular variant, where all parts (morning coat or waistcoat, and trousers) are the same colour and material, often grey, and usually called "morning suit" or "morning grey" to distinguish it; considered properly appropriate only to festive functions, such as summer weddings and horse races, which consequently makes it slightly less formal. The correct hat would be a formal top hat, or if on less spacious audience settings, optionally a collapsible equivalent opera hat.

Debrett's states that morning dress should not be specified as the dress code for events starting after 6 p.m. If a formal event will commence at or after 6 p.m., white tie should be specified instead. The semi-formal daytime counterpart of this code is the black lounge suit.

Formal hall or formal meal is a meal held at some of the oldest universities in the United Kingdom and the Republic of Ireland (as well as some other Commonwealth countries) at which students usually dress in formal attire and often gowns to dine. These are held commonly in the colleges of Oxford, Cambridge and Durham, at Trinity College Dublin (where they are known as commons), and in some halls and colleges at St Andrews, and the Australian sandstone universities (Adelaide, Melbourne, Queensland, Sydney, Tasmania, Western Australia), and at Trinity College, Toronto.

In a number of redbrick universities, such as Manchester, Bristol, Leeds and Exeter, some halls practise similar traditions in order to increase interaction between academics and students, and to enrich the students' overall learning experience. Colleges of some Australian redbrick universities, including the Australian National University, Monash University, the University of New England, the University of New South Wales and the University of Southern Queensland, also hold gowned formal dinners.