Definition of Thumb
Thumb: The short thick finger situated at an angle to the other fingers so it can be opposed to the them, making it possible to pick up and hold things. The thumb is analogous in position to the big toe (the great toe) and similarly has only two phalanges (all the other digits have three).
Last Editorial Review: 6/14/2012
Back to MedTerms online medical dictionary A-Z List
Need help identifying pills and medications?
Get the latest health and medical information delivered direct to your inbox FREE!