Answer Description
The three types of authentication are something you KNOW, something you HAVE, and something you ARE. A multifactor authentication uses 2 or more of these factors. A credit card is something you HAVE while a PIN is something you know.
Wikipedia
Multi-factor authentication is an electronic authentication method in which a computer user is granted access to a website or application only after successfully presenting two or more pieces of evidence (or factors) to an authentication mechanism: knowledge (something only the user knows), possession (something only the user has), and inherence (something only the user is) It protects the user from an unknown person trying to access their data such as personal ID details or financial assets Two-factor authentication (also known as 2FA) is a type, or subset, of multi-factor authentication It is a method of confirming users' claimed identities by using a combination of two different factors: 1) something they know, 2) something they have, or 3) something they are
Multi-factor_authentication - Wikipedia, the free encyclopedia