| NMCC | Music Composition Core public namespace |
| NChords | Reviewed catalog of named chords stored in program memory |
| CScaleChord | One chord found on a scale degree |
| CAccidental | Chromatic alteration of a letter, from -4 (quadruple flat) to +4 (quadruple sharp) |
| CChord | A chord pattern spelled from a root note name |
| CChordPattern | Root-independent chord structure: up to seven ascending tones within two octaves |
| CChromaticIndex | Absolute semitone position of a pitch, with origin C-1 = 0 |
| CEqualTemperament | Twelve-tone equal temperament relative to a Tuning |
| CInterval | Directed interval: a diatonic step count and a chromatic semitone count (SPEC-INT-1) |
| CIntervalNumber | 1-based interval number: 1 unison, 3 third, 8 octave, 10 tenth (SPEC-INT-2, SPEC-INT-3) |
| CIntervalQuality | Interval quality: perfect, major, minor, or augmented/diminished repeated one to four times (SPEC-INT-4) |
| CKey | A tonic and a diatonic mode, with the key signature they imply |
| CKeySignature | Key signature: zero to seven sharps or flats (SPEC-KEY-1) |
| CMeter | Exact written time signature and its simple/compound interpretation |
| CNotationOptions | Options for text output (SPEC-TXT-3) |
| CNote | A written pitch combined with an exact written note value |
| CNoteName | Written note name: a letter plus an accidental, without octave |
| CNoteValue | Exact written note length: a power-of-two base and zero to four dots |
| CPitch | Written absolute pitch: a note name plus an octave |
| CPitchClass | Pitch class 0-11 with spelling discarded (C = 0) |
| CRhythmPattern | Cyclic onset/rest pattern on a grid of equal steps |
| CScale | A scale pattern spelled from a root note name |
| CScalePattern | Root-independent scale structure: up to twelve ascending degrees |
| CTuning | Tuning reference: a written pitch and its frequency in hertz |