What does the term "dynamics" refer to in music?

The term "dynamics" in music specifically refers to the volume of sound, describing how loud or soft music is played. This aspect of music is crucial as it adds emotional expression and contrast to a piece, allowing composers and performers to convey intensity or delicacy. For instance, crescendo indicates a gradual increase in volume, while decrescendo indicates a decrease. Understanding dynamics helps musicians interpret a score more fully and enriches the listening experience, providing depth and nuance beyond mere melody and rhythm. The other options pertain to different musical elements, such as tempo, structure, and notation, but they do not relate to the concept of volume in sound.