lullaby
noun /ˈlʌləbaɪ/
/ˈlʌləbaɪ/
(plural lullabies)
- a soft, gentle song sung to make a child go to sleep
- She sang her baby a lullaby.
Word Originmid 16th cent.: from lull + bye-bye, a sound used as a refrain in lullabies; compare with bye-byes.