Study of the past (7)
I believe the answer is:
history
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">study of the past</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for history that I've seen before include "Account of past events" , "'... repeats itself'" , "eventful past" , "Old record" , "Time passed" .)