An ivory cutter (7)
I believe the answer is:
incisor
This might be a double definition.
'an ivory' is the first definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'cutter' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for incisor that I've seen before include "Canine" , "carnivore requires?" , "One takes a bite" , "companion could be Goofy" , "Type of tooth" .)