Curved structure (4)
(Other definitions for dome that I've seen before include "Cupola - millennium building" , "Rounded roof with circular base" , "Rounded vault of a roof" , "Hemispherical roof" , "Crown" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">curved structure</span>' is the definition.<br/ ><span class="explanation-format__explanation">(architectural structure)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for arch that I've seen before include "Inner side of foot" , "Supporting structure" , "Curve that spans an opening" , "Bend into upward curve" , "Devilish" .)