Funnel shape (4)
I believe the answer is:
'funnel shape' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cone that I've seen before include "Dry fruit of many evergreen trees, say pine" , "Circular pyramid" , "Figure (for traffic control?)" , "standing in middle of motorway" , "Movable plastic bollard" .)