Bird laugh (4)
I believe the answer is:
lark
This clue might be a double definition.
'bird' is the first definition.
(lark is a kind of bird)
'laugh' is the second definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
Can you help me to learn more?
(Other definitions for lark that I've seen before include "Amusing escapade; bird" , "One gets up early" , "Foolish activity, songbird" , "High-flying songbird" , "bit of mischief" .)