Distinct period (3)
I believe the answer is:
era
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">distinct period</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 era that I've seen before include "US equality law" , "Important time" , "Age of importance" , "Aeon" , "quite some time" .)