An under shirt, also known as an undershirt or a vest, is a garment worn under a shirt or blouse to provide additional warmth or as a sweat-absorbing layer. Other synonyms for an under shirt include a singlet, a tank top, a camisole, a sleeveless shirt, a body shirt, an undergarment, and a base layer. These synonyms describe an article of clothing that is typically made of soft, lightweight materials and is designed to fit snugly against the skin. Under shirts are commonly worn by both men and women and are available in a variety of styles and colors to suit different preferences and needs.