A measurable physical characteristic or personal behavioral trait used to recognize the identity, or verify the claimed identity, of an applicant. Facial images, fingerprints, and iris scan samples are all examples of biometrics.
NIST SP 800-12 Rev. 1
Automated recognition of individuals based on their biological and behavioral characteristics.
NIST SP 800-63-3
The science and technology of measuring and statistically analyzing biological data. In information technology, biometrics usually refers to automated technologies for authenticating and verifying human body characteristics such as fingerprints, eye retinas and irises, voice patterns, facial patterns, and hand measurements.