The part between one's teeth? (3)
I believe the answer is:
bit
'the part' is the definition.
(both mean a piece of something)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for bit that I've seen before include "scrap" , "Sank teeth in" , "Small fragment" , "Binary digit; small piece" , "Small quantity or piece of metal for a horse" .)