Le déjeuner sur l'herbe

Third stream is a hybrid genre that intentionally merges the languages of jazz and Western classical music. Coined by composer and horn player Gunther Schuller in 1957, the term describes music that is neither "jazz with strings" nor classical music with a swing veneer, but a true synthesis. It typically combines classical forms (such as fugue, theme and variations, or concerto-like structures) and orchestration with jazz harmony, rhythm, and improvisation. The results range from chamber-sized works for jazz combo and string quartet to large pieces for orchestra and jazz soloists. Third stream pieces often alternate between fully notated sections and improvised passages, use counterpoint and extended harmony, and may blend straight and swung time feels within a single work.

Progressive big band is a post–World War II evolution of big band jazz that shifts the focus from dance music to concert-oriented, highly arranged works. It preserves the massed brass-and-reeds power of swing-era ensembles, but adopts bebop’s advanced harmony and lines, classical orchestration techniques, and ambitious, often through-composed forms. Arrangers favored expanded instrumentation (French horns, tuba, Latin percussion, sometimes strings), dense voicings, polytonality, and dramatic dynamic contrasts, yielding a bold, modernist “concert jazz” sound. Compared with swing, the rhythm can alternate between a hard-driving 4/4, even-eighth feels, Latin grooves, and unusual meters, while sections trade contrapuntal lines more than riff-based call-and-response. The result is an epic, sometimes imposing aesthetic that bridged jazz and contemporary classical ideas.

Big band is a large-ensemble style of jazz and popular dance music built around brass, reed, and rhythm sections playing arranged parts. Typical instrumentation includes five saxophones (often doubling clarinet/flute), four trombones, four trumpets, and a rhythm section of piano, guitar, upright bass, and drum set. The music emphasizes swing rhythms, call-and-response between sections, riff-based writing, and dramatic shout choruses, while leaving space for improvised solos. Born in American ballrooms and theaters, big band became the sound of the Swing Era, providing both music for dancing and a platform for sophisticated arranging and orchestration that shaped much of 20th‑century jazz and popular music.