register; recording machine
Refers to a device that records or registers information, such as a cash register or a data entry terminal.
The clerk recorded the sales on the register.
レジ is the common everyday term for a cash register or checkout counter, while 登録機 is a more formal or technical term for a recording/registering device.
cash register
Standard kanji spelling using 機 (machine).
Variant using 器 (device); less common but understood.
Compound of 登録 (registration) and 機 (machine).