Glossary

Plain-language definitions of the terms used across these concepts. Where a term has its own page, follow the link to explore it further.

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Accidental: A sharp (♯) or flat (♭) that raises or lowers a note by a half-step. On a piano, the black keys.
Amplitude: The size of a sound wave, heard as loudness. It is independent of pitch.
Arpeggio: A chord played one note at a time instead of all together.

Cadence: A short chord move that resolves to the tonic, such as V to I.
Chord: Three or more notes heard together as a single harmonic unit.
Chord progression: A sequence of chords moving through time, the backbone of a song.
Chord quality: The kind of chord - major, minor, diminished and so on - set by its stacked intervals.
Chords in a key: The chords that belong to a key: the diatonic seven, named with Roman numerals.
Chromatic: A note outside the current key. The opposite of diatonic.
Circle of fifths: The twelve keys arranged in a ring, each a perfect fifth from the next.
Consonance: A combination of notes that sounds settled and at rest.

Diatonic: Belonging to the major scale and its modes: seven notes spread across the octave.
Dissonance: A combination of notes that sounds tense and wants to move.
Dominant: The chord on the fifth degree of a scale: the most tense, pulling back to the tonic.
Dynamics: How loud or soft music is played, and the way that changes over time.

Enharmonic equivalent: Two written names for the same note, such as A♯ and B♭.

Frequency: How fast a sound vibrates, measured in hertz. We hear it as pitch.

Key: A tonic note plus the scale and chords built on it: a piece of music’s home.
Key signature: The sharps or flats that define a key, written at the start of the staff.

Leading tone: The seventh degree of a scale, a half-step below the tonic, which pulls up to it.

Major scale: The reference seven-note scale, with the step pattern whole-whole-half-whole-whole-whole-half.
Melody: Notes in sequence: the horizontal relationship between pitches.
Mode: A scale formed by starting the major scale on a different degree, such as Dorian.

Note: The neutral identity of a pitch, like a single piano key. Its written spelling is a separate idea.

Octave: The distance between a note and the next note of the same name, at double the frequency.

Scale: An ordered ladder of notes spanning an octave, set by a pattern of steps.
Scale degree: A note’s position within a scale, counted from the tonic as 1 to 7.
Semitone (half-step): The smallest step in our system: one key to the very next, black or white.
Subdominant: The chord on the fourth degree of a scale, establishing movement away from the tonic.

Timbre: The tone colour that makes a piano and a violin sound different on the same note.
Tonic: The home note of a key: its most stable note and centre of gravity.
Transposition: Moving music to a different key while keeping every interval the same.