A biometric system is a technological system that uses information about a person (or other biological organism) to identify that person. Biometric systems rely on specific data about unique biological traits in order to work effectively. A biometric system will involve running data through algorithms for a particular result, usually related to a positive identification of a user or other individual.
Techopedia explains Biometric System
The specific nature of today’s biometric systems is associated with a specific use of the term "biometrics." In general, biometrics is any use of biological data in technology. Biometric systems focusing exclusively on the identification of humans have become the major kind of biometric system in today’s IT world.
Governments, businesses and organizations can use biometric systems to get more information about individuals or about a populace as a whole. Many biometric systems are developed for security applications. An airport scanning device, a "bio-password" system, or an internal data gathering protocol is an example of a biometric system that uses identifying data for a security result.