Tree, you heard (3)
I believe the answer is:
yew
'tree' is the definition.
(type of tree)
'you heard' is the wordplay.
'heard' shows a homophone (sound like).
'you' sounds like 'YEW'.
(Other definitions for yew that I've seen before include "feature of many graveyards" , "This tree grows in churchyard" , "Longbow wood" , "Evergreen tree with dark needles and red berries" , "Leaving body" .)