Book division (7)
I believe the answer is:
chapter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">book division</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for chapter that I've seen before include "religious assembly" , "Division of written work" , "Book division - assembly of canons" , "Cathedral body" , "series of events" .)