Iroquois tribe (6)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">iroquois tribe</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 seneca that I've seen before include "Roman statesman, philosopher and playwright" , "philosopher in Rome" , "Roman stoic; US Indian" , "Stoic, Nero's tutor" , "Dramatist" .)