In a narrow sense, a fingerprint is an impression made by the friction ridge of a human finger. Recovery of fingerprints from crime scene is an important method in forensic medicine. Through the natural secretion of sweat from the endocrine glands present in the epidermal ridge, fingerprints are easily deposited on suitable surfaces (such as glass, metal or polished stone). These are sometimes referred to as "opportunity displays.".

In the broader use of the term, fingerprints are marks on the friction ridges of any part of the hand of a human or other primate. The marks on the sole of the foot will also leave friction marks.

When inks or other substances are transferred from the peaks of friction ridges on the skin to relatively smooth surfaces (such as fingerprint cards), intentional fingerprint imprints may be formed. Fingerprint records usually include marks on the pad of the last joint of the finger and thumb, although fingerprint cartoons often record the lower part of the finger.

Human fingerprints are very detailed, almost unique, difficult to change and lasting in the life cycle of an individual, making them suitable as long-term markers of human identity. They may be employed by the police or other authorities to identify those who wish to conceal their identity, or to identify those who are unable or have died, so that they cannot prove their identity, for example after a natural disaster. Since the early 20th century, fingerprint analysis technology has been used, resulting in many crimes to be solved. This means that many criminals think gloves are essential. In 2015, it has been reported to identify gender by testing the biochemical content of fingerprints rather than the visual pattern.