A tenth part (5)
I believe the answer is:
tithe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a tenth part</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 tithe that I've seen before include "Charge" , "10% tax" , "Gift of tenth" , "Tenth of income given to church" , "Levy, originally worth one tenth" .)