In mathematics, a digit is a symbol or numeral that is used to represent an integer in a positional number system. Examples of digits include the decimal characters "0" through "9", the binary characters "0" or "1", and the hexadecimal digits "0"..."9","A",...,"F." The word comes from the Latin digitus for finger or toe, and retains this meaning – reminding us of the origins of our base 10 number system. The earlier Indo-European root deik is related to many other words that hark back to the use of the hands and fingers to "point" out objects, including index, indicate, token, and teach.

In anatomy, a digit is any part of the pentadactyl limb of vertebrates that contains a linear group of phalanges. A primate finger or toe.