camiseta
/kamiˈseta/ · B1 · noun · f
jersey
👕 camisa (shirt) + -eta (small) = a little shirt
Camisa is Spanish for shirt, and -eta is a suffix that makes things small. So a camiseta is a little shirt: the short-sleeved T-shirt, as opposed to the full button-up camisa. Like camisa, it ends in -a and is feminine: la camiseta.