Trumpet or bugle (4)
I believe the answer is:
horn
This clue is a double definition.
'trumpet' is the first definition.
(I know that trumpet can be written as horn)
'bugle' is the second definition.
(thesaurus)
(Other definitions for horn that I've seen before include "Head growth; cornucopia" , "Instrument - rhino's feature" , "Musical instrument; Chile Cape" , "Head appendage; warning instrument" , "Cusp" .)