Children’s game inside cottage (3)
I believe the answer is:
tag
'children's game' is the definition.
(I've seen this in another clue)
'inside cottage' is the wordplay.
'inside' indicates a hidden word.
'TAG' can be found hidden inside 'cottage'.
(Other definitions for tag that I've seen before include "Children's chasing game" , "Name" , "Label (to attach)" , "stock quotation" , "Label - children's game" .)