The tricorne or tricorn is a style of hat that was popular during the 18th century, falling out of style by 1800, though actually not called a "tricorne" until the mid-19th century. During the 18th century, hats of this general style were referred to as "cocked hats". At the peak of its popularity, the tricorne varied greatly in style and size, and was worn not only by the aristocracy, but also as common civilian dress, and as part of military and naval uniforms. Typically made from animal fiber, the more expensive being of beaver-hair felt and the less expensive of wool felt, the hat's most distinguishing characteristic was that three sides of the brim were turned up (cocked) and either pinned, laced, or buttoned in place to form a triangle around the crown. The style served two purposes: first, it allowed stylish gentlemen to show off the most current fashions of their wigs, and thus their social status; and secondly, the cocked hat, with its folded brim, was much smaller than other hats, and therefore could be more easily tucked under an arm when going inside a building, where social etiquette dictated that a gentleman should remove his hat. Tricornes with laced sides could have the laces loosened and the sides dropped down to provide better protection from the weather, sun, and rain.
Tricornes had a rather broad brim, pinned up on either side of the head and at the back, producing a triangular shape. The hat was typically worn with one point facing forward, though it was not at all unusual for soldiers, who would often rest a rifle or musket on their left shoulder, to wear the tricorne pointed above their left eyebrow to allow better clearance. The crown is low, unlike the steeple hats worn by the Puritans or the top hat of the 19th century.
Tricornes ranged from the very simple and cheap to the extravagant, occasionally incorporating gold or silver lace trimming and feathers. In addition, military and naval versions usually bore a cockade or other national emblem at the front. This style of hat remains in use in a number of countries to the present day as an item of ceremonial dress.