Fingerprint
A fingerprint was a pattern on one's digits that could be used to confirm one's identity via biometrics. A fingerprint of a thumb was called a thumbprint. They were included on identity tapes. On Ferenginar, Ferengi used dermal prints as means of signatures. A thumbscan was a biometric identification consisting of an image of an individual's thumbprint.

In 2153, Commander Trip Tucker used his thumbprint to enter the locked quarters of T'Pol. ()

A fingerprint match helped confirm the bodily death of Rao Vantika. ()

A Cardassian's thumbprint on a Kressari PADD was all the evidence Kira Nerys needed in 2370 to prove to the Chamber of Ministers a connection between Cardassia and The Circle. Once the thumbprint established the shocking truth behind The Circle, Minister Jaro Essa's attempted a coup d'etat against the Bajoran Provisional Government immediately collapsed. ()

Thumbprints could be used in lieu of signatures. In 2374, Luther Sloan threatened Julian Bashir with confinement in a maximum security cell for the duration of the Dominion War unless he put his thumbprint on a confession. ()

See also 
 Fingerprint database
 Footprint
 Handprint

External link 
 
Anatomy
Identification technology