1. The study or use of the finger alphabet, as among deaf-mutes.
2. Talking" or communicating with the fingers and hands.
3. A method of communication used by deaf-mutes, involving symbolic expressions with the fingers and hands.
4. The study of fingerprints for purposes of identification: The following illustration provides evidence that dactylology indicates that a thief must be very large as shown by the size of the prints left by his fingers.

The use of dactylology can provide evidence from a crime scene that an important method of forensic science, or the use of technical methods to solve crimes, can be utilized to find out who committed them.