Happening, occurrence (5)
I believe the answer is:
event
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">happening</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">occurrence</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for event that I've seen before include "Occasion; sports contest" , "game, perhaps" , "Function" , "Fixture" , "A notable occurrence or happening" .)