lullaby Meaning, Definition & Usage

  1. noun a quiet song intended to lull a child to sleep
    cradlesong; berceuse.
  2. noun the act of singing a quiet song to lull a child to sleep
    cradlesong.

WordNet

lull"a*by noun
Etymology
From Lull, v. t.
Definitions
  1. A song to quiet babes or lull them to sleep; that which quiets. Shak.
  2. Hence: Good night; good-by. Obs. Shak.

Webster 1913