A "jazz idiom" in music refers to the unique musical characteristics, language, and syntax that define the genre of jazz. The term encompasses various elements such as harmony, rhythm, melody, form, and improvisation.
Jazz is a musical style that originated in African American communities in the late 19th and early 20th centuries, primarily in New Orleans. The genre is known for its improvisational nature and its incorporation of blues, swing, and ragtime musical styles.
The harmonies in jazz are often characterized by advanced chord progressions, substitutions, and reharmonization techniques. The rhythm in jazz is characterized by syncopation, swing, and various rhythmic subdivisions, such as triplets and hemiola. The melody in jazz is often influenced by the blues and is characterized by the use of "blue notes," which are slightly flattened thirds, sevenths, and ninths.
One of the key elements of the jazz idiom is improvisation, where musicians play without a predetermined score and spontaneously create music in the moment. Improvisation in jazz is based on a strong understanding of chord progressions, melody, and other musical elements. Jazz musicians often rely on their understanding of these elements, as well as their own musical creativity and instincts, to create unique and inventive solos.
The form of jazz compositions can vary greatly, ranging from simple blues progressions to complex and elaborate compositions. Jazz musicians often use various forms such as the blues, 32-bar song form, and various forms of through-composed works.
In conclusion, the jazz idiom encompasses a wide range of musical elements that define the genre of jazz. These elements include harmony, rhythm, melody, form, and improvisation, all of which contribute to the unique and innovative sound of jazz. The jazz idiom continues to evolve and has influenced numerous other musical styles and genres.
Source: "Jazz: A History of America's Music" by Geoffrey C. Ward and Ken Burns.