American university (4)
I believe the answer is:
yale
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">american university</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for yale that I've seen before include "security device" , "Heraldic animal" , "Mass. university" , "US university; lock" , "New Haven university" .)