<P> The build of an A-shirt is simple: the neck and armholes are often reinforced for durability . One usually has large armholes and neck holes and a neckline that can reach down as far as the bottom of the chest . (Women's A-shirts have smaller holes, to conceal their breasts .) They are also sometimes made long to make tucking into a pair of jeans / shorts easier . In almost all cases, they are buttonless, collarless, and pocketless . An A-shirt worn as an undershirt is designed for a tight fit and is often made of ribbed cotton . </P> <P> A tank top consists of a sleeveless shirt with low neck and different shoulder straps width . It is named after tank suits, one - piece bathing suits of the 1920s worn in tanks or swimming pools . The upper garment is worn commonly by both men and women . </P> <P> A camisole, also called just cami, is a sleeveless undergarment for women, normally extending to the waist . They often have spaghetti straps . Originally worn as an undershirt, like the A-shirt they have become increasingly used as warm - weather outerwear . The camisole is usually made of satin, nylon, or cotton . </P> <P> A dudou ("belly cover"), known as a yem in Vietnamese contexts, is an item of East Asian clothing resembling an silk apron or bib but traditionally used as an undershirt or bodice to flatten the figure and, medicinally, to preserve stomach qi . Beginning around the year 2000, Western and Chinese fashion has also begun incorporating them as a sleeveless and backless shirt for women . </P>

Where did the term tank top come from