Welcome to the Payments 101 Course!

If you’re new to payments, you’ll quickly notice this industry has its own language—filled with terms like acquirer3-D Secure (3DS)clearing, and settlement. For beginners, this jargon can feel overwhelming.

That’s why I created this Payments Glossary: a simple, easy-to-use guide that explains these terms in clear and short definitions. Think of it as your ready reference—a page you can return to anytime you need to recall what a term means or explain a concept to someone else.

By the end of this glossary, you’ll be able to:


Payment Processing

Four-Party Model


On-Us Transaction


Off-Us Transaction


Security & Authentication

3DS (3D Secure)


PARes (Payer Authentication Response)