Catholic church service (4)
I believe the answer is:
mass
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">catholic church service</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for mass that I've seen before include "Celebration of the Eucharist, especially in the RC Church" , "Rite; quantity of matter" , "Religious rite" , "Body of matter" , "Great deal" .)