Rectangle (6)
I believe the answer is:
oblong
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rectangle</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 oblong that I've seen before include "Log on B (anag.)" , "Plane figure that deviates from a square by elongation" , "Elongated rectangle" , "Roughly rectangular" , "Oval" .)