A waistcoat, often known as a vest in American English, is a sleeveless upper-body garment traditionally worn over a dress shirt and underneath a suit jacket as part of men's formal wear. Characterized by its V-neckline, it typically has a button-down front and can be made from various materials, including silk, cotton or wool. The back is often made of satin or similar material, with an adjustable strap for a perfect fit. It adds a layer of sophistication and style to an ensemble and can be in a matching or contrasting colour to the suit.