Fundamental musical terms are defined to help all people understand the organized structure of music. Music uses arrangements of sound, melody, harmony, texture, rhythm, and dynamics. Melody is the rhythmic progression of modulated pitches over time, while harmony combines two or more simultaneous notes and texture can be monophonic, polyphonic, homophonic, or heterophonic. Rhythm comes in flowing, random, regular, or progressive forms and dynamics show the volume of produced sounds.