Merchant's partner's material stolen from 1D (5)
I believe the answer is:
ivory
'merchant's' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for ivory that I've seen before include "Jumbo's dentine" , "National emblem" , "Elephant tusk material" , "pasty" , "Film director" .)