Thames at Oxford (4)
I believe the answer is:
isis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">thames at oxford</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 isis that I've seen before include "Si, si - an Egyptian goddess" , "God" , "Exists twice for a goddess" , "Divine female" , "Old Egyptian fertility goddess" .)