About, before a date (5)
I believe the answer is:
circa
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">about before a date</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 circa that I've seen before include "About (regarding dates)" , "Approximately, around" , "More or less" , "Approximately (of a year)" , "About, say, a date" .)