Twelve-bar blues
A twelve-measure harmonic pattern, commonly built around the tonic, subdominant, and dominant chords, used in blues and related music.
I–IV–V progression: A harmonic pattern built from the tonic, subdominant, and dominant chords of a key. The twelve-bar blues is a distinctive twelve-measure realization of this broader three-chord pattern.
Musical measure: A segment of musical time defined by a specified number of beats. The form counts twelve such segments, whose beat groupings shape its length.
African-American music: Music created within African-American communities, encompassing diverse traditions and genres. The twelve-bar blues emerged within this broad musical history.
Chicago blues: An urban blues style associated with Chicago, electric instruments, and amplified ensembles. Its bands often expand the twelve-bar pattern with electric guitar, harmonica, and rhythm section.
Eight-bar blues: A blues chorus organized into eight measures rather than twelve. It condenses the blues cycle into fewer measures and different harmonic pacing.
Blues turnaround: A short phrase or chord progression that leads from the end of a blues chorus back to its beginning. The final measures often use a turnaround to make the cycle restart smoothly.
Tonic (music): The first scale degree and the tonal center of a musical key. The tonic chord anchors the cycle and establishes its home key.
Blues: A musical genre and tradition rooted in African-American communities in the southern United States. The twelve-bar pattern became one of the genre’s best-known harmonic structures.
Jump blues: An upbeat, dance-oriented blues style featuring small ensembles, strong rhythms, and often saxophones. Its arrangements use blues choruses to drive energetic, tightly arranged performances.
Sixteen-bar blues: A blues chorus organized into sixteen measures, often extending or altering familiar blues harmonies. Its longer span contrasts with the twelve-measure cycle while retaining blues conventions.