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 (1830sā1910s). 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.