Transitional event (4,2,7)
I believe the answer is:
rite of passage
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">transitional event</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 rite of passage that I've seen before include "Ceremony marking stage of life" , "The Wedding, perhaps?" , "Formative experience" , "Significant event during a transitional period in life" , "Very important life event" .)