The Collaborative International Dictionary of English v.0.48:
cradlesong \cradlesong\ n. a quiet song that lulls a child to sleep. Syn: lullaby. [WordNet 1.5]WordNet (r) 3.0 (2006):
cradlesong n 1: a quiet song intended to lull a child to sleep [syn: lullaby, cradlesong, berceuse] 2: the act of singing a quiet song to lull a child to sleep [syn: lullaby, cradlesong]