Circle or hexagon (5)
I believe the answer is:
shape
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">circle or hexagon</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 shape that I've seen before include "Good physical form" , "Control development of" , "Heaps (anag.)" , "Phase (anag.)" , "Square, circle, etc." .)