Theory dictionary
Every term in one honest sentence. These are the same plain-language definitions the Theory Aide extension shows as tooltips inside Ableton Live.
- bar A group of beats, most often four, marked by the heavier grid lines.
- beat The steady pulse under music, the thing your foot taps.
- borrowed A chord taken from the parallel major/minor for extra color.
- chord Several notes sounding together, heard as one object with a mood.
- circle of fifths The twelve keys arranged in a wheel so neighbors differ by one note. Distance on the circle is harmonic distance.
- consonance The smooth, settled quality of intervals whose waves fit together simply.
- contour The overall shape of a melody: where it rises, peaks, and falls.
- contrary motion Two voices moving in opposite directions. The most independent, strongest motion.
- density How many notes sound at once or in quick succession. How full it feels.
- dissonance The rough, restless quality of intervals whose waves never settle.
- dominant The tension chord that wants to fall back to the tonic (the V).
- frequency How many times per second something vibrates. In sound, faster means higher.
- hertz The unit for frequency: one hertz is one back-and-forth per second.
- hidden fifth Both voices leap the same direction into a 5th, a softer parallel-5th.
- hidden octave Both voices leap the same direction into an octave.
- interval The distance between two notes, counted in semitones and heard as a flavor.
- key The gravity field of a scale: one note is home, and every other note is heard by its distance from home.
- melody A sequence of single notes heard as one continuous line with a shape.
- oblique motion One voice holds while the other moves.
- octave The distance between a note and the note vibrating twice as fast. They sound like the same note, higher.
- parallel fifths Two voices a 5th apart moving the same direction, the classic counterpoint no-no.
- parallel motion Two voices moving the same direction by the same interval.
- parallel octaves Two voices an octave apart moving together, collapsing two lines into one.
- pitch How high or low a note sounds, set by its frequency.
- register How high or low the notes sit overall.
- root The note a chord is built from and named after.
- scale A chosen set of notes defined by a pattern of steps, repeating every octave.
- secondary dominant A V chord aimed at a chord other than the tonic, briefly making it feel like home.
- semitone The smallest step on the piano roll: one row up or down. Twelve make an octave.
- similar motion Two voices moving the same direction by different amounts.
- subdominant Harmony that pulls away from home and sets up tension (the IV side).
- syncopation Accents landing off the strongest beats, giving a pushed, lively feel.
- tempo How fast the beats come, measured in beats per minute (BPM).
- tonic The home chord or note, where the music feels at rest.
- triad The basic three-note chord: a root, a third, and a fifth, stacked.
- voice One continuous musical line in a texture, whether or not anyone is singing.
- voice leading How each line moves note-to-note from one chord to the next.