TERM:
Multi-factor authentication

Definition:

An approach to security authentication, which requires that the user of a system provide more than one form of verification in order to prove their identity and gain access to the system. Multi-factor authentication takes advantage of a combination of several factors of authentication; three major factors include verification by something a user knows (such as a password), something the user has (such as a smart card or a security token), and something the user is (such as the use of biometrics).