Digit was a term used to describe a toe, finger, or thumb. The term was predominantly used by the Malcorians. Types of fingers on a hand, in addition to thumb, included forefinger or index finger, ring finger, and pinkie.
In 2153, Jonathan Archer was given the finger of a Kessick, a Xindi-Humanoid working at the trellium mining planet by the mine's alien foreman, to prove that the individual in question was in fact Xindi. Although Doctor Phlox was able to use the severed finger to compare Kessick's genetic profile with that of a Xindi-Reptilian, he later stated that a blood sample or saliva "would have sufficed." (ENT: "The Xindi")
In late 2369, Vedek Bareil Antos told Commander Benjamin Sisko that he knew a monk, when he was five years old, who could "squeeze the pagh right out of you with his thumb and forefinger". (DS9: "In the Hands of the Prophets")