Western dress codes are dress codes in Western culture about what clothes are worn in what setting. Classifications are traditionally divided into formal attire (full dress), semi-formal attire (half dress), and informal attire, with the first two sometimes in turn divided into day and evening wear. A level below these are sometimes referred to as casual attire, often in combinations such as "smart casual" or "business casual" in order to indicate higher expectation than none at all.
The more formal traditional Western dress code interpretations — that is formal i.e. "white tie" and semi-formal i.e. "black tie" — have remained highly codified for men with essentially fixed definitions mostly unchanged since the 20th century with roots in 19th century customs. For women, though, changes in fashion have been more dynamic. Yet, although casual inventions, combinations and reinterpretations of the classifications have occurred and fluctuated, the general formal traditions have persisted for more than a century.
Dress codes are sometimes explicitly instructed, expected by peer pressure, or followed intuitively.
As with other cultures, versions of ceremonial dresses, military uniforms, religious clothing, academic dresses, and national dresses appropriate to the formality level are generally permitted and worn as exceptions to the uniformity, often in the form of headgear (see biretta, kippah etc.). Conversely, since most cultures have at least intuitively applied some level equivalent to the more formal ones in Western dress code traditions, the latter's versatile framework open to amalgamation of international and local customs have influenced its competitiveness as international standard range from formal to casual.