A finger or toe. In the basic limb structure of terrestrial vertebrates there are five digits (see pentadactyl limb). This number is retained in humans and other primates, but in some other species the number of digits is reduced. Frogs, for example, have four fingers and five toes, and in ungulate (hooved) mammals, the digits are reduced and their tips are enclosed in horn, forming hooves.
Subjects: Biological Sciences — Medicine and Health.