Sum preceder
I believe the answer is:
ergo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sum preceder</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ergo that I've seen before include "Hence" , "Therefore - what a goer" , "as a consequence" , "Therefore (Latin)" , "so philosopher wrote in Latin" .)