Oval shape (7)
I believe the answer is:
ellipse
'oval shape' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ellipse that I've seen before include "See pill (anag) - oval" , "Shape - sell pie (anag)" , "Inclined plane through a cone" , "Geometrical oval" , "Egg-shaped geometrical figure" .)