Beer only inside the plant (4)
I believe the answer is:
aloe
'the plant' is the definition.
(aloe is a kind of plant)
'beer only inside' is the wordplay.
'beer' becomes 'ale' (I've seen this before).
'only' becomes 'o' (this could be a standard abbreviation which I don't know about).
'inside' is an insertion indicator.
'ale' going around 'o' is 'ALOE'.
Can you help me to learn more?
(Other definitions for aloe that I've seen before include "Flower, maybe vera" , "Succulent plant (4) 5532" , "Succulent plant (may be bitter!)" , "Genus of bitter herbs" , ". . . . vera, soothing plant" .)