"Rhythm Changes" refers to a chord progression derived from the song "I Got Rhythm" by George Gershwin. This progression typically follows a 32-bar AABA form, where the A sections feature a specific set of chords, and the B section introduces a contrasting harmonic sequence. This chord structure is widely used in jazz and has become a foundation for countless compositions and improvisations. Musicians often create new melodies over these changes, allowing for creative expression while maintaining a familiar harmonic framework. The versatility of "Rhythm Changes" makes it a staple in jazz repertoire.