cajero
/kaˈxeɾo/ · B2 · noun · m
teller
💵 caja (cash box) + -ero (the person who) = the one who runs the till
Caja means box, and also the cash register or checkout. The ending -ero marks a person's job, as in zapatero (shoemaker). So the cajero is the till person. A cash machine is also a cajero automático.