Using two or more different forms of identification to authenticate a user. The common single-factor method employs one password. For more security, multi-factor authentication (MFA) adds at least one more form that is different such as a text message with a one-time number, a physical token or a form of biometrics. See
two-factor authentication.
Multi-Factor Fatigue
MFA is widely used and no doubt prevents a lot of fraud. However, people may not have their phone handy to serve as a second form of authentication when logging into a website at their computer. Hopefully, in the future, no passwords will be the norm (see
FIDO).