The science of using biological property, such as fingerprints, to identify individuals. Popular in sci-fi movies, it refers to voice, fingerprint, skin, or retinal identification. It is increasingly used in the real world, for example, Erin's laptop has a biometric fingerprint password protection, as does one version of the iPhone released in 2013.
U.S. law enforcement also uses biometrics to identify criminals. Since it is no longer necessary to use ink, biometrics make it easy and affordable to "fingerprint" people. In fact, fingerprint and facial recognition technology is becoming an everyday occurence especially at the Department of Motor Vehicles, arrival gates at airports, in schools, and in corporate America (especially in the banking and securities industries). Facial recognition is even in some police patrol cars because it searches databases very quickly. Future uses may include e-commerce transaction signatures identified by biometric means.
Historical perspective: Remember January, 2001 when fans attending the Superbowl in Tampa were surprised to learn their faces had been captured by camera and then scanned against the database of suspected felons? That is an example of facial recognition biometrics.