Introductory (11)
I believe the answer is:
preliminary
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">introductory</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for preliminary that I've seen before include "Initial -- action before the main event" , "Done in preparation" , "Preparatory action" , "First" , "Introductory (measure or statement)" .)