Subtitle (7)
I believe the answer is:
caption
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">subtitle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(caption is a kind of subtitle)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for caption that I've seen before include "Pontiac (anag)" , "Brief description of an illustration" , "Elegance of dress" , "Provide (a picture) with a title" , "accompanying message" .)