Track shape (4)
I believe the answer is:
oval
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">track shape</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 oval that I've seen before include "Egg-like" , "Ellipsoidal" , "Where a duck may be broken" , "sports ground" , "Stretched circle?" .)