acquirer (card acquirer)
A card acquirer is a financial institution or payment service provider that operates on the merchant side of a card-payment network. It typically handles merchant onboarding, routes authorization and settlement messages, and enables funds from card sales to reach the merchant. In ATM services, the acquirer may instead operate or manage the cash-dispensing arrangement that fulfills a cardholder's withdrawal.
Source: European Central Bank (ECB) (source). This glossary entry is an independently worded adaptation of the cited information.