A flat cap is a rounded cap with a small stiff brim in front, originating in Northern England. The hat is known in Scotland as a bunnet; in Wales as a Dai cap; and in the United States as a scally cap, English cap. Various other terms exist. Flat caps are usually made of tweed, plain wool, or cotton, while some are made using leather, linen, or corduroy. The inside of the cap is commonly lined for comfort and warmth.

A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. The origin of the word "cap" comes from the Old French word "chapeau" which means "head covering". Over time, the word has evolved and changed its meaning, but it still retains its association with headwear. Caps typically have a visor, or no brim at all. They are popular in casual and informal settings, and are seen in sports and fashion. They are typically designed for warmth, and often incorporate a visor to block sunlight from the eyes. They come in many shapes, sizes, and are of different brands. Baseball caps are one of the most common types of cap.