Elliptical shape (4)
I believe the answer is:
oval
'elliptical shape' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oval that I've seen before include "6D 5A [TUBE STATION]" , "Race track" , "sports ground" , "It's egg-shaped for cricketers" , "Cricket ground - presidential office" .)