Chord Symbols

Jazz chord symbols are a compact notation system that conveys the root, quality, and extensions of a chord in a single alphanumeric label. The root is a capital letter (C, F♯, B♭, etc.) followed by abbreviations that specify the chord's structure. Understanding these symbols is essential for reading lead sheets and "faking" through a standard.

The basic quality indicators are: major triad (C), minor triad (Cm or C–), augmented triad (C+), and diminished triad (C°). Adding a seventh turns the chord into a four-note chord: Cmaj7 is a major triad with a major seventh; C7 is a dominant seventh (major triad, minor seventh); Cm7 is a minor seventh chord; C°7 is a fully diminished seventh; and Cø7 (or Cm7♭5) is a half-diminished seventh.

Extensions stack thirds above the seventh: the ninth, eleventh, and thirteenth. A symbol like C9 implies a dominant seventh plus a major ninth (C7 with an added 9). Alterations modify these extensions with sharps or flats: C7♯9 (the "Hendrix chord") has a raised ninth; C7♭9 has a lowered ninth; C7♭5 has a flatted fifth. The symbol C13 implies all the lower extensions are present and the thirteenth is added on top. Brackets or "add" notation specify additions without implying intermediate extensions (Cadd9 adds a ninth without a seventh).

Slash chords appear as C/E, indicating a C major chord over an E bass note — root in the numerator, bass note in the denominator. Suspended chords replace the third: Csus4 has a perfect fourth in place of the third; Csus2 has a major second. Reading chord symbols fluently is the foundation of jazz harmony, since performers are expected to realize these symbols spontaneously in a performance.