The thumb is one of five digits on each hand, but it has a different shape and function from the other digits. However, most medical guides refer to the thumb as a finger. Also known as the pollex or digitus primus manus, the thumb is anatomically different from the hand’s other four digits.

We do have eight fingers because the thumb technically isn’t a finger. It looks similar to our fingers on the outside in some ways, but in all of the ways it doesn’t, that’s because it is not. It is, however, also a digit.

A thumb is a digit, but not technically a finger. Many people don’t make the distinction between thumbs and other digits. How many fingers do you have? Your answer might depend on whether you consider your thumb to be a finger.

Digit: The thumb counts as a digit but not a finger in the strict sense. According to NLM: The national library of medicine (which is closely involved in the naming of scientific and medical terms) classifies "thumb" under the term "fingers" in its hierarchy.