Church book
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">church book</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 psalter that I've seen before include "Book of religious songs" , "Church chanting book" , "Book for church use" , "Book of sacred songs" , "Cherub-like" .)