Lullaby
LULLABY, a cradle-song, a song sung to children to " lull " them to sleep; the melody being styled in Fr. berceuse and in Ger. Wiegenlied. " Lull," cf. Swed. Mia, Du. lullen, etc., is of echoic or onomatopoeic origin, cf. Lat. lallare, to chatter.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)