Caught batter Root (4)
I believe the answer is:
beet
'root' is the definition.
(I know that beet is a type of root)
'caught batter' is the wordplay.
'caught' shows a homophone (sound like) (heard).
'batter' becomes 'beat'.
'beat' is a homophone of 'BEET'.
(Other definitions for beet that I've seen before include "E.g. chard, mangelwurzel" , "Crop plant, sugar source" , "The mangelwurzel, for instance" , "An edible root plant" , "Root, maybe source of sugar" .)