The crossword question is likely asking for the setting of the popular lullaby “Rock-a-Bye Baby.” The answer to this question is TREETOP. This is because one of the lyrics in the song says, “When the wind blows, the cradle will rock. When the bough breaks, the cradle will fall. Down will come baby, cradle and all.” Here, the baby’s cradle is depicted as being situated in a treetop, which would sway in the wind and cause the cradle to rock. Eventually, the bough – or branch – breaks, causing the cradle to fall to the ground. So, the answer to the crossword question is TREETOP, which is the setting of the “Rock-a-Bye Baby” song.