Part of a church at right angles to the nave (8)
I believe the answer is:
transept
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of a church at right angles to the nave</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for transept that I've seen before include "Crossing part of a church" , "Patterns in part of church at right angle to nave" , "Part of a church at right angles to the nave" , "Cross-aisle in church" , "Part of church intersecting nave" .)