Bat turned over to uncle (7)
I believe the answer is:
noctule
'bat' is the definition.
Both the answer and definition are singular nouns.
Maybe there's a link between them I don't understand?
'turned over to uncle' is the wordplay.
'turned over' indicates anagramming the letters.
'to'+'uncle'='touncle'
'touncle' with letters rearranged gives 'NOCTULE'.
Can you help me to learn more?
(Other definitions for noctule that I've seen before include "Large insectivorous bat" , "Great bat -- largest in Britain" .)