Plain-English definitions of the terms a student of scales, modes, intervals, and chord vocabulary will run into.
A scale is a sequence of notes between a starting pitch and that pitch one octave higher, ordered by pitch. Most scales have seven notes; some have five (pentatonic), six (whole-tone, hexatonic blues), or eight (octatonic). The interval pattern between consecutive notes — measured in semitones — defines the scale's identity. Apply the same pattern to a different tonic and you get the same scale in a different key.
A mode is a scale produced by starting the same interval pattern from a different note. The major scale's seven modes (Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian) all share the same set of notes but each places the half-steps in a different position relative to the tonic. The result is seven distinct moods from one collection of pitches.
The tonic is the first scale degree — the note the scale starts on and the pitch the music feels pulled toward. In C major the tonic is C; in A minor the tonic is A. Modes shift the tonic without changing the underlying note collection.
An interval is the pitch distance between two notes, measured in semitones or by interval name (minor 3rd, perfect 5th, etc.). Intervals are the building blocks of every scale, chord, and melody. The 13 simple intervals span Unison through Perfect Octave.
A semitone (also called a half-step) is the distance from one note to the next on a piano keyboard — including the black keys — or from one fret to the next on a guitar. Twelve semitones make an octave. The half-step is the building block from which all larger Western intervals are constructed.
Two notes an octave apart sound 'like the same note' even though one is twice the frequency of the other. The octave is the interval Western music repeats at: every C, every G, every B♭ shares the same pitch class. Scales are typically defined within one octave; multi-octave scale displays simply repeat the pattern at higher registers.
A key signature is a row of sharps or flats at the start of a staff that tells the player which notes are altered throughout. C major has no sharps or flats; G major has one sharp (F♯); F major has one flat (B♭). The key signature lets the engraver avoid writing accidentals on every note that would otherwise need one.
A diatonic melody, chord, or scale uses only the seven notes of a parent key signature. The C major scale is diatonic to C major; G7 is diatonic to C major; F♯ is not. The opposite is chromatic — using notes outside the parent key.
Chromatic notes are pitches that don't belong to the active key. A chromatic passing tone is a note borrowed temporarily for colour. The chromatic scale uses all 12 semitones in sequence. Chromaticism distinguishes 20th-century jazz, late-Romantic harmony, and bebop vocabulary from purely diatonic styles.
The leading tone is the 7th note of the major scale or harmonic minor (♮7). It sits a semitone below the tonic and 'wants' to resolve upward to it. The presence of the leading tone is what makes harmonic minor sound less wistful than natural minor — and what makes V7 chords feel like they need to resolve to I.
The tritone is the interval of three whole tones — six semitones — between, for example, C and F♯. It bisects the octave exactly: the inversion of a tritone is another tritone. Historically called the 'devil in music' for its unstable, restless sound, the tritone is the defining tension in dominant 7th chords (between the 3rd and the ♭7).
A pentatonic scale uses five notes per octave instead of the diatonic seven. The major pentatonic (1 2 3 5 6) and minor pentatonic (1 ♭3 4 5 ♭7) appear independently in nearly every folk tradition worldwide. The reduced note count makes them forgiving over chord changes — every note 'fits'.
The blues scale is the minor pentatonic with one added pitch — the flatted 5th (♭5). The resulting six-note set is the starting vocabulary of blues, rock, and modern guitar improvisation. The ♭5 is treated as a passing tone rather than a stable resting point.
Modal jazz, pioneered by Miles Davis on Kind of Blue (1959), shifts the focus from fast chord-change navigation to extended sections over a single mode. 'So What' is built on D Dorian. 'Impressions' on the same. The freedom to develop a melodic idea over many bars (rather than every two beats) defined post-bebop jazz.
Transposing instruments (Bb clarinet, alto sax, French horn, etc.) read music written at a different pitch than what they actually sound. A Bb clarinet reading a written C produces a sounding B♭. The convention saves the player from learning multiple sets of fingerings as the instrument size changes within an instrument family.
A clef anchors one staff line to a specific pitch. The treble clef (G clef) fixes the second-from-bottom line as G4. The bass clef (F clef) fixes the second-from-top line as F3. The alto and tenor clefs (C clefs) fix the middle line as C4. Different instruments use different clefs to keep their typical range within the staff.
A fingering is the assignment of player's fingers to notes. On piano, fingerings are numbered 1 (thumb) through 5 (pinky) per hand. On guitar, the left-hand fingers (1 = index through 4 = pinky) plus a fret + string position. Pedagogical scale references typically include suggested fingerings for the conventional ascending / descending pattern.
Verovio is an open-source music engraving library developed by the RISM Digital Center. It reads MEI (Music Encoding Initiative) markup and emits professional-quality SVG or PDF notation. ScaleMastery's engraved scales are rendered live by Verovio at request time from typed Score trees produced by Fuaran.Music.
MEI (Music Encoding Initiative) is an XML-based standard for representing musical notation in machine-readable form. It's the format Verovio reads to produce engraved output. Like MusicXML, MEI captures the visual + semantic structure of notation; unlike MusicXML, MEI is more scholarly / archival-oriented and is the format research-grade engravers prefer.