Define Rock-a-bye Meaning

Rock-a-bye
It's an interjection, always used to settle a baby or child down to sleep.

"rock-a-bye, Baby," sang Alfred in strident tones and he swung the child high in his arms.
By Emmy
Rock-a-bye Baby

The most common version used today is:

Rock-a-bye baby, in the treetop,

When the wind blows, the cradle will rock,

When the bough breaks, the cradle will fall,

And down will come baby, cradle and all.
By Dosi