The term 'HAT' is a 3-letter word that can refer to either a beret or a bowler. A beret is a soft, round, flat-crowned HAT typically made of wool felt or cotton. It is often worn as a fashion accessory and is associated with the military and certain subcultures. A bowler, also known as a derby HAT, is a hard felt HAT with a rounded crown and narrow brim. It was popularized in the 19th century by British and American actors and is now commonly worn as part of formal attire.