# Glossary ⚠️(Deprecated)
- An Online Payment Webpage – An online payment system that allows to easily embed a payment module in any kind of Online Shop.
- Online Shop – A webpage or an application, which allows the customer to purchase an item or a service via the internet.
- Merchant – A retail trade or service company that possesses an Online Shop.
- A Merchant Primary Fields –A Company information, mandatory to be registered as a Merchant.
- A Merchant iPay Parameter –A Merchant information that should be provided to a Bank to allow a Company to perform payments on an Online Payment Webpage.
- A Card Number (`PAN`) – A 16-digit number displayed on the front of the plastic card.
- An Amount Blocking – A card operation that results in the reservation (making unavailable) of the portion (amount) of the card balance. After this, the Amount Blocking should - be approved (Amount Deduction) or the Amount should be Unblocked and thus become available again.
- A Pre-authorization – A two-step payment method. On a first step an amount is reserved from a customer’s account/card balance, while on a second step an operation is being completed (amount deduction)
- Callback – A request performed by the Bank System to a service published by an Online Shop to provide updated information regarding the payment.
- A System Credentials - A `client_id` and the `secret_key` provided to a Company once it has been successfully registered in the Bank system as a Merchant and has filled in all necessary data.