Item on a library shelf (4)
I believe the answer is:
tome
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">item on a library shelf</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tome that I've seen before include "Big book" , "Large scholarly volume" , "dictionary?" , "War and Peace, say" , "Hefty volume" .)