lullabyPronunciation: /ˈlʌləbʌɪ/Translate lullaby | into French | into German | into Italian | into Spanish Definition of lullaby noun (plural lullabies) a quiet, gentle song sung to send a child to sleep. verb (lullabies, lullabying, lullabied) [with object] rare sing to (someone) to get them to go to sleep:she lullabied us, she fed usOrigin: mid 16th century: from lull + bye-bye, a sound used as a refrain in lullabies; compare with bye-byeslullaby in other Oxford dictionaries Definition of lullaby in the US English dictionary