digit (n.)

mid-15c., "pertaining to numbers below ten;" 1650s, "pertaining to fingers," from Latin digitalis, from digitus "finger or toe" (see digit). The numerical sense is because numerals under 10 were counted on fingers. Meaning "using numerical digits" is from 1938, especially of computers which run on data in the form of digits (opposed to analogue) after c. 1945. In reference to recording or broadcasting, from 1960.

1660s, in zoology, "having separate fingers and toes," from Latin digitatus "having fingers or toes," from digitus "finger" (see digit). In botany, "having deep, radiating divisions, like fingers," by 1788.