www.webmd.com
What Are the Benefits of Singing Lullabies to Babies? - WebMD
A lullaby is a calming song used to relax a baby and lull them to sleep. These songs have different ancient origins, but most include modern music. Parents have included lullabies in their child's bedtime routine for years. A lullaby is generally based on a 6/8 time signature with a gentle, rhythmic melody.