Seashell (5)
I believe the answer is:
conch
'seashell' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for conch that I've seen before include "Large shell used as trumpet" , "Marine mollusc with a spiral shell" , "Large spiral shell" , "Type of shell" , "Big spiral-shelled mollusc" .)