Nursery bed (4)
I believe the answer is:
crib
'nursery bed' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for crib that I've seen before include "Cot; translation cheat" , "Bed; manger" , "Cot - cattle stall - copy during an exam" , "Nativity scene; copy illicitly" , "Nativity centrepiece" .)