Amassment (10)
I believe the answer is:
collection
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">amassment</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for collection that I've seen before include "Part of service" , "Offertory" , "whip-round" , "Number of accumulated items" , "Group" .)