From The Collaborative International Dictionary of English v.0.48 :
Cash register \Cash register\ A device for recording the amount of cash received, usually having an automatic adding machine and a money drawer and exhibiting the amount of the sale. [Webster 1913 Suppl.]From WordNet (r) 3.0 (2006) :
cash register n 1: a cashbox with an adding machine to register transactions; used in shops to add up the bill [syn: cash register, register]