Teeth (5)
'teeth' is the definition.
(fang is a kind of tooth)
This is all the clue.
(Other definitions for fangs that I've seen before include "Large pointed teeth" , "Teeth of, say, wolf" .)
'teeth' is the definition.
(cog is a kind of tooth)
This is the entire clue.
(Another definition for cogs that I've seen is " Teeth on the edge of a wheel".)
'teeth' is the definition.
(I know this)
This is all the clue.
(Another definition for molars that I've seen is " Grinding back teeth".)