Day or period of celebration (8)
I believe the answer is:
festival
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">day</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I have seen 'Day of celebration ' mean 'festival' so perhaps 'day' could also mean 'festival')</span><br/ ><br/ >'<span class="explanation-format__original">period of celebration</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for festival that I've seen before include "Edinburgh's summer event" , "Celebratory period" , "Day set aside for celebration" , "Lift vase (anag.)" , "holiday?" .)