The document defines the key elements of music as melody, rhythm, harmony, timbre, form, dynamics, and texture. Melody is a sequence of single notes that form the main musical line. Rhythm organizes notes into patterns of different durations. Harmony consists of chords, which are two or more notes played together. Timbre refers to the quality or "color" of a sound produced by different instruments. Form describes the order and relationship of sections in a piece of music. Dynamics involve changes in volume, and texture describes the relationship between lines or voices within a piece.