Stradivari's mentor
I believe the answer is:
amati
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stradivari's mentor</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for amati that I've seen before include "fine cello" , "instrument-maker" , "fiddler" , "Famous violin family" , "Famous violin maker" .)