PSP
From Innopaydia
Abbreviation of Payment Service Provider. A payment service provider (PSP) offers merchants online services for accepting electronic payments by a variety of payment methods including credit card, bank-based payments such as direct debit, bank transfer, and real-time bank transfer based on online banking. Some PSPs provide unique service to processes other next generation methods (E-Payment Providers) including eWallets (PayPal), Cash (Western Union), prepaid cards or vouchers, and even paper or e-check processing.
source: www.wikipedia.org