Concise guide
How to read chord symbols
A chord symbol summarizes pitch content and bass function. Read it from left to right:
Core chord qualities
Intervals are measured from the root. R means root.
CMajor: R · 3 · 5
CmMinor: R · ♭3 · 5
CdimDiminished: R · ♭3 · ♭5
Caug or C+Augmented: R · 3 · #5
Csus2Suspended: R · 2 · 5
Csus4Suspended: R · 4 · 5
Major is implied. A bare letter such as C means a major triad. The lowercase m explicitly indicates minor.
Sevenths and extensions
C7
Dominant seventhR · 3 · 5 · ♭7The plain 7 implies a minor seventh.
Cmaj7
Major seventhR · 3 · 5 · 7“maj” applies to the seventh.
Extensions continue above the octave: 9 = 2, 11 = 4, and 13 = 6. A plain 9, 11, or 13 normally implies a dominant seventh unless another quality is stated.
C9R · 3 · 5 · ♭7 · 9
Cmaj9R · 3 · 5 · 7 · 9
Cm9R · ♭3 · 5 · ♭7 · 9
Cadd9R · 3 · 5 · 9; no seventh
“Add” is literal. It adds the named pitch without implying the intervening seventh.
Alterations, bass notes, and omissions
Lower or raise that chord tone by one semitone: C7♭9, C7#11.
Changes the root itself: D♭7 is built on D-flat.
C/E means a C chord with E as its lowest note.
“No R,” “no 3,” or “no 5” states which expected chord tone is absent.
Diminished-seventh terminology
Cm7♭5
Half-diminishedR · ♭3 · ♭5 · ♭7Also written Cø7.
Cdim7
Fully diminishedR · ♭3 · ♭5 · 𝄫7Also written C°7. The diminished seventh sounds like a major sixth.
Chord symbol versus voicing
A chord symbol identifies a harmonic structure; it does not prescribe a unique fingering. A voicing determines register, note order, doublings, and omissions. Context—especially the bass line, melody, and surrounding harmony—may support more than one valid name for the same pitch collection.
Reference principle
Interpret symbols by separating the root, chord quality, extensions, alterations, bass note, and stated omissions. When the symbol is ambiguous, musical context determines the most useful analysis.