Book section (7)
I believe the answer is:
chapter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">book section</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 chapter that I've seen before include "reading- matter" , "Sequence - section of book - church body" , "one section of book" , "series of events" , "Book division - assembly of canons" .)