A berceuse is a lullaby, particularly one performed in 6/8 time, a rhythm meant to suggest a rocking motion. Fittingly, it derives from the French bercer (“to rock”) and ultimately the Old French noun bers (“cradle”). While the German Johannes Brahms was known for his lullabies, berceuse appears in the names of works by French composers including Camille Saint-Saëns and Maurice Ravel.
Clara celebrates her Nutcracker with a polka; Fritz and the other boys disrupt the girls’ lullaby berceuse with a battery of toy instruments; the battle scene pitting Clara’s dolls and Fritz’s hussars against the mice is a percussion riot.
— Jeffrey Gantz, The Boston Globe, 30 Nov. 2018