lull·a·by (lŭl'ə-bī') n.
pl.lull·a·bies A soothing song with which to lull a child to sleep. tr.v.
lull·a·bied, lull·a·bying, lull·a·bies To quiet with or as if with a lullaby.
[Obsolete lulla, word used in lullabies (from Middle English lullai, from lullen, to lull; see lull) + bye2.]