Shape with ten sides (7)
I believe the answer is:
decagon
'shape with ten sides' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for decagon that I've seen before include "10-sided figure" , "Ten-sided plane figure" , "Go, dance on geometric figure with ten sides" , "Figure with 10 sides" , "A polygon -- eg can-do (anag)" .)