Berceuse

A berceuse is "a musical composition usually in 6/8 time that resembles a lullaby". Otherwise it is typically in triple meter. Tonally most berceuses are simple, often merely alternating tonic and dominant harmonies; since the intended effect is to put a baby to sleep, wild chromaticism would be somewhat out of character. Another characteristic of the berceuse, for no reason other than convention, is a tendency to stay on the "flat side"; noted examples including the berceuses by Chopin, who pioneered the form, Liszt, and Balakirev, which are all in D♭.