The label is upside down. It often is (3)
I believe the answer is:
bat
'it often is' is the definition.
The definition suggests a singular noun which matches the answer.
'the label is upside down' is the wordplay.
'the label' becomes 'tab' (I've seen this before).
'is upside down' says the letters should be written in reverse.
'tab' in reverse letter order is 'BAT'.
Can you help me to learn more?
(Other definitions for bat that I've seen before include "Creature" , "once wielded by 60 [GREIG]" , "Nocturnal animal - racket" , "Cricket, table-tennis and baseball implement" , "Small flying mammal, may be vampire" .)