A Merchant ID (MID) is a unique, alphanumeric identification code provided to a business by a payment processor or acquiring bank. It serves as a digital "address" for a business within the payment ecosystem, ensuring that when a customer swipes or enters their card, the funds are routed to the correct merchant bank account.

An Independent Sales Organization (ISO) is a third-party company that partners with acquiring banks and payment processors to sell merchant services and payment processing solutions to businesses. ISOs act as intermediaries between merchants seeking payment processing capabilities and the financial institutions that provide the underlying banking infrastructure for card transactions.

A merchant account is a specialized business bank account that enables companies to accept and process credit card and debit card payments from customers. This account acts as an intermediary holding area where funds from card transactions are temporarily stored before being transferred to your primary business bank account, typically within 1-3 business days.