Final answer:
The meter of Brahms's Lullaby is triple meter, characterized by three beats per measure with the first beat being stressed, creating a rhythm similar to a waltz.
Step-by-step explanation:
The meter of Brahms's Lullaby is triple meter. In music, triple meter refers to a rhythmic pattern with three beats to a measure, where the first beat is usually stressed, and the remaining two are less so. When looking at poetry, Brahms's lullaby isn't a poem but a musical piece; nonetheless, it still possesses a rhythmic quality analogous to poetic meter. Johannes Brahms's famous lullaby, officially titled "Wiegenlied: Guten Abend, gute Nacht" (Op. 49, No. 4), is traditionally performed with a lilting, soothing 3/4 time signature that exemplifies its triple meter structure, meaning it has a rhythm where each measure is divided into three beats. This creates the familiar waltz-like pattern that we associate with many classic lullabies and is what makes it so effective as a soothing song for children.