Rafter (4)
I believe the answer is:
beam
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rafter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for beam that I've seen before include "Ship's width; ray" , "Column of light" , "Smile broadly or radiate" , "Smile, light shaft" , "A broad smile like lunar ray" .)