Shout, bellow (4)
I believe the answer is:
yell
This clue is a double definition.
'shout' is the first definition.
(I know that shout can be written as yell)
'bellow' is the second definition.
(I've seen this in another clue)
(Other definitions for yell that I've seen before include "roar" , "Scream" , "Loud utterance" , "Howl" , "Loud cry; rhymes with collapsed" .)