128 Fun Facts About Music Theory

The mnemonic 'Every Good Boy Does Fine' names the lines of which clef?

Treble: the symbol is a stylised letter G that curls around the G line, which is why it is also called the G clef.

Which orchestral instrument is the main user of the alto clef?

Viola: the alto clef puts middle C on the centre line, which suits the instrument's middle range, while cellos, bassoons and trombones borrow the tenor clef for high passages.

What are the short extra lines that carry notes too high or low for the staff called?

Ledger lines: instruments use different clefs partly to avoid them, because each clef keeps a part's usual range on the staff.

In scientific pitch notation, middle C is written how?

C4: octave numbers tick up at every C, not at A as the alphabet suggests, so the B just below middle C is B3.

Which mark, written just after a note, makes it last half as long again?

A dot: it adds half the note's value, so a dotted half note fills a whole bar of waltz time, and a second dot adds half as much again.

What do British musicians call the whole note?

Semibreve: the name means half a breve, which was a short note in medieval music (Latin for 'short'), yet it is now the longest note in common use.

In the 13th century, Franco of Cologne codified a notation in which each note's shape shows what?

Its duration: until then singers worked out long and short notes from context by learned rules, so his treatise let rhythm be read straight off the page.

The lower number of a time signature is normally what kind of number?

A power of 2: it names the note value being counted, and note values come from halving, so 2 means half notes, 4 quarters and 8 eighths.

Which of these time signatures is a compound meter?

6/8: compound meters split each beat into three, so its six eighth notes are felt as two big beats, not six.

Lalo Schifrin's theme for Mission: Impossible is written in which time signature?

5/4: Schifrin joked he wrote it 'for people from outer space who have five legs', and the 1996 film's remake by two members of U2 squared it into dance-friendly 4/4.

A key signature with a single sharp indicates which major key?

G major: its scale needs F raised to F-sharp so that the last step up to G is a half step, and E minor borrows the same signature.

Which step pattern builds a major scale?

W W H W W W H: whole and half steps in that order, so on a piano's white keys from C the half steps fall where no black key sits, at E–F and B–C.

Which diagram arranges the twelve keys so neighbours differ by one sharp or flat?

Circle of fifths: each step clockwise lands a fifth higher and adds one sharp, and Mykola Dyletsky drew a version of it in a treatise of the 1670s.

Which key is the relative minor of C major?

A minor: a relative minor starts three half steps below its major and shares its key signature, so a stray G-sharp is the usual tell that a tune is really in the minor.

Which rock guitar chord is just a root and its fifth?

Power: with no third the power chord is neither major nor minor, and the bare fifth stays crisp under heavy distortion where fuller chords turn muddy.

In just tuning, the perfect fifth has which frequency ratio?

3:2: the upper note vibrates three times for every two of the lower, the smooth blend violinists listen for when tuning, because the violin is tuned in fifths.

The tuning system named after Pythagoras was written down long before him in which civilisation?

Ancient Mesopotamia: its clay tablets tell musicians to tune by alternating fifths and fourths, and later writers credited the method to the Greek philosopher instead.

Which interval is nicknamed 'the devil in music'?

Tritone: named for the three whole tones it spans, it runs all through Bernstein's West Side Story, where the song 'Maria' opens on its uneasy leap.

The first two notes of 'Here Comes the Bride' leap up by which interval?

Perfect fourth: ear-training students memorise that leap with this tune or the opening of 'Amazing Grace', a trick known as a reference song.

Playing only white keys from D up to D gives which mode?

Dorian: Miles Davis built 'So What' on little else, staying on D Dorian for sixteen bars before sliding up a half step to E-flat Dorian.

Which mode is a major scale with its fourth degree raised by a half step?

Lydian: on the white keys it runs F to F, but medieval chant so often flattened its fourth note, B, that the mode slid into what we now call F major.

Every triad built from the notes of a whole-tone scale has which quality?

Augmented: every note sits a whole step from the next, so any triad stacks two major thirds, and that rootless blur is why film scores use the scale for dream sequences.

In C major, which three notes form the key's only diminished triad?

B, D and F: two minor thirds stacked on the scale's seventh note, the leading tone, which is why the chord pulls so strongly back to C.

When a chart just says 'seventh chord' with no qualifier, which type is usually meant?

Dominant: chord symbols assume a major triad and a minor seventh unless told otherwise, so a bare D7 means D, F-sharp, A and C.

The chord progression IV–I is widely nicknamed which cadence?

Amen cadence: hymns so often set their closing 'Amen' to those two chords that the name stuck, though its formal name is the plagal cadence.

A cadence in which V resolves to a chord other than the tonic, usually vi, is called what?

Deceptive: the chord that arrives shares two of the tonic's three notes, so the ear is fooled for a moment and the real ending is put off; it is also called an interrupted cadence.

Ending a minor-key piece on a major tonic chord is known as what?

Picardy third: a minor chord was long thought too dissonant to end on, which helped the habit take hold, and the Beatles close 'And I Love Her' with the same twist.

A Neapolitan chord is a major chord built on which altered scale degree?

Flat second: in C that gives a D-flat major chord, usually played with F in the bass, and the sixth from that F up to D-flat is why it is called the Neapolitan sixth.

Spelled with different note names, Wagner's Tristan chord turns out to be which everyday chord?

Half-diminished seventh: respelled, its four notes make that common chord, but Wagner resolves it onto another dissonance, so the opera's key stays in doubt from the opening bars.

What does the dynamic marking pp stand for?

Pianissimo: the Italian ending -issimo means 'very', so pp is 'very soft', and the suffix stacks, which is why a third p turns the word into pianississimo.

What does the abbreviation sfz ask a performer to do?

Play one note suddenly loud: sforzando is Italian for 'forcing', and the jolt covers only the note or chord it sits on, so the earlier volume returns straight afterwards.

Which composer marks a bassoon solo pppppp, six p's, in his Sixth Symphony?

Tchaikovsky: although the score gives the passage's last four notes to the bassoon, orchestras commonly hand them to a bass clarinet instead.

In a score, a hairpin that opens from left to right tells players to do what?

Get gradually louder: the widening wedge is shorthand for crescendo, Italian for 'growing', and its mirror image, closing to a point, means the opposite.

What does the tempo marking andante literally mean?

Walking pace: andante is a form of the Italian verb andare, 'to go', so the music should simply keep moving at an easy stroll.

Which Italian tempo term simply means 'quickly' and is faster than allegro?

Presto: it means only 'quick', which is why stage conjurers took it up for their patter, whereas allegro literally means 'cheerful' and so hints at a mood as well.

Which Italian tempo marking literally means 'broad'?

Largo: its most famous example is a misnomer, since Handel's 'Largo', the aria 'Ombra mai fu', is marked larghetto, the diminutive form, in his score.

Who patented the metronome that Beethoven marked his tempos with?

Maelzel: he took the pendulum design of his Amsterdam rival Dietrich Winkel, added a numbered scale and sold it under his own name, hence the 'M.M.' on old tempo markings.

Which notation symbol is drawn like an eye under an arched brow?

Fermata: Italian for 'a stop', it tells a player to hold a note beyond its written length, and how much longer is left to the performer or conductor.

The instruction da capo literally means 'from the' what?

Head: capo is Italian for it, so da capo sends players back to the top of the piece, while the coda at the far end takes its name from the Latin for 'tail'.

Staccato is Italian for what?

Detached: the word is the past participle of the Italian staccare, 'to detach', so each note is clipped short, leaving a sliver of silence before the next.

Legato is Italian for what?

Tied together: legato comes from the Latin ligare, 'to bind', the root of 'ligament', so the notes run into one another with no gaps, usually under a curved slur.

Two notes written differently but sounding the same pitch, like C-sharp and D-flat, are what?

Enharmonic: on a piano the two share one black key, but in older meantone tunings they were slightly different pitches, which is one reason notation keeps both names.

Old meantone tunings left one fifth so harshly out of tune that musicians named it after which animal?

Wolf: eleven of the twelve fifths were tuned almost pure, leaving the last, usually G-sharp to E-flat, to howl, so composers kept to keys that avoided it.

The ISO 16 standard fixes which note at 440 Hz?

A above middle C: the figure was only agreed internationally in 1939; before that, French law had set the same note at 435 Hz and Britain had settled on 439.

Which instrument traditionally sounds the note that the rest of the orchestra tunes to?

Oboe: the usual explanation is its penetrating tone, which cuts through the orchestra so that every player can hear the note to match.

In 1859 France fixed concert pitch by law because ever-rising pitch was straining which performers?

Singers: instruments could be rebuilt to play sharper but voices could not, so the law pulled the pitch back down to 435 Hz, a standard that much of Europe then took up for a time.

In equal temperament, what is the frequency ratio between adjacent semitones?

The twelfth root of two: about 1.0595, the one ratio that lands twelve equal steps exactly on the octave, at the price of nudging every other interval slightly off its pure tuning.

Zhu Zaiyu, who calculated equal temperament precisely in 1584, was a prince of which dynasty?

Ming: Zhu was descended from one of the dynasty's emperors, and the Flemish scholar Simon Stevin reached the same idea independently in a manuscript that stayed unpublished until 1884.

An octave holds 1,200 of which tuning unit?

The cent: each equal-tempered semitone holds 100 of them, hence the name, and a single one is too small for the ear to pick out as a step between notes.

A sharp or flat written beside a single note, outside the key signature, is called what?

An accidental: the name comes from an old word for a non-essential quality, because the sign alters one note without changing the key of the passage.

The hymn 'Ut queant laxis', source of the solfège syllables, is sung each 24 June for the feast of which saint?

John the Baptist: each phrase of the hymn starts one note higher than the last, so its opening syllables, ut, re, mi, fa, sol and la, became the names of the six notes.

English-speaking teachers changed which solfège syllable to 'ti' so that no two would start with the same letter?

Si: it clashed with sol, so in the 19th century it became te and then ti in Britain and the United States, while the Romance languages kept si as the note's everyday name.

Which everyday word for 'the whole range' began as the name of the lowest note in the medieval scale?

Gamut: it fuses gamma, the Greek letter that marked the lowest note, with that note's syllable, ut, and the word then stretched to cover the whole scale and any full range.

The Guidonian hand was a mnemonic that helped medieval choirs learn to do what?

Sight-sing: every joint and fingertip of the left hand stood for one note of the medieval scale, though the complete version only appears after Guido's own lifetime.

What were the basic notation marks used for chant before the five-line staff existed?

Neumes: the earliest showed only the rise and fall of a melody, so they worked as reminders of a chant already learned by ear, not as a way to read a new one.

The frequencies of the harmonic series relate to the fundamental how?

As whole-number multiples: a note with a 100 Hz fundamental also sounds at 200, 300, 400 Hz and beyond, and the balance among those layers gives each instrument its own tone colour.

A note one octave above 440 Hz has what frequency?

880 Hz: each octave doubles the frequency, so the ear hears 220 to 440 Hz and 440 to 880 Hz as steps of the same size even though the second gap is twice as wide.

A single MIDI cable carries sixteen what, each for a separate instrument?

Channels: each one can be routed to a different device, so a single cable can run a whole rack of synthesisers, and General MIDI keeps channel 10 for drums.

Which Italian score marking calls for every performer to join in after a solo passage?

Tutti: Italian for 'all', the same word that turns up in tutti-frutti, which literally means 'all fruits'.

In sonata form, what is the section between the exposition and the recapitulation called?

Development: here the opening themes are broken up and driven through one key after another, the unrest that the recapitulation settles by bringing everything back in the home key.

The word ostinato comes from the Italian for what?

Stubborn: the word is a cousin of 'obstinate', and the figure earns it by repeating without budging, like the snare-drum rhythm that never changes from start to finish of Ravel's Boléro.

Placing accents where they would not normally fall, making the music 'off-beat', is called what?

Syncopation: a tie, a rest or a sudden accent pushes the stress onto a weak beat or between beats, the jolt heard in styles as different as ragtime, rock and rap.

The rhythmic term hemiola comes from the Greek for what?

One and a half: a hemiola squeezes three beats into the time of two, and three is one and a half times two; the word first described that proportion between two pitches.

Josef Matthias Hauer's 1919 'law of the twelve tones' just preceded which composer's better-known twelve-tone method?

Arnold Schoenberg: the two Austrians worked independently, and where his method fixes all twelve notes in a set order, the tone row, Hauer sorted them into unordered six-note halves called tropes.

A left-hand pattern that breaks each chord into the order lowest, highest, middle, highest is named after which composer?

Alberti: Domenico Alberti used the figure so heavily that it took his name, though he was not the first to write it, and Mozart opens his Sonata in C, K. 545, with it.

When the most common type of clarinet plays a written C, which concert pitch sounds?

B-flat: its music is written a whole tone above what sounds, so the same fingerings match the same written notes on every size of clarinet and a player can swap between them freely.

Which instrument sounds an octave lower than written?

Double bass: its part is written an octave above the sound so that the notes sit on the staff instead of far below it, and the guitar is notated the same way.

A pentatonic scale that contains no semitones is called what?

Anhemitonic: an- means 'without' and a hemitone is a half step, so the five black keys of a piano, none of them a half step from the next, make a scale of exactly this kind.

Raising the seventh of a natural minor scale creates which interval between its sixth and seventh degrees?

Augmented second: the leap is three half steps wide, awkward enough to sing that the melodic minor scale raises the sixth degree as well to smooth it out.

The flat sign descends from a rounded form of which letter?

b: chant scribes wrote a round b for the lower of the two pitches the note B could take and a square b for the higher, and the square one later became the natural and sharp signs.

Which Viennese court composer published Gradus ad Parnassum, the 1725 treatise that laid out five species of counterpoint?

Johann Joseph Fux: Haydn taught himself counterpoint by working through its exercises one by one, and Beethoven prized the book too.

In species counterpoint, what is the simple, unchanging part the student writes against called?

Cantus firmus: Latin for 'fixed melody'; the student weaves new lines against it under tight rules, which is why the method is nicknamed strict counterpoint.

What name is given to the fifth species of counterpoint, which combines the first four?

Florid: the word means 'flowery', and this last stage lets the student blend every earlier rhythm into one freely decorated line that starts to sound like real music.

Bach's Well-Tempered Clavier pairs each prelude with which contrapuntal form?

The fugue: the name comes from the Latin for 'flight', because the voices that enter later seem to chase the one that set off alone.

What is a chord called when its notes are sounded one after another rather than together?

Arpeggio: the word comes from the Italian for playing the harp, an instrument on which chords are naturally rolled out one note after another.

The word 'chord' derives from which older word meaning agreement or harmonious sound?

Accord: it goes back to the Latin for 'heart', as in hearts in agreement; Middle English clipped it to 'cord', and the spelling with an h only appeared around 1600.

If do is a major key's home note, which solfège syllable is home for its relative minor?

La: choirs that keep the major key's syllables simply treat la as home in the minor, a system known as la-based minor.

In counterpoint, what is the motion called when one voice holds its note while the other moves?

Oblique: the word means 'slanting', and of the four kinds of motion it is the only one in which a voice stands still while its partner climbs or falls.

Which time signature can be written as a large C on the staff, a symbol known as 'common time'?

4/4 has four quarter-note beats in every bar. The C is not a letter at all but a broken circle: a full circle once stood for triple time.

'Row, Row, Row Your Boat' and 'Frère Jacques' are which kind of song, sung with staggered entries?

Round singing has every voice perform exactly the same melody, each starting at a different time. The oldest surviving one in English is 'Sumer is icumen in'.

Which Italian phrase describes singing with no instrumental accompaniment at all?

A cappella literally means 'in the style of the chapel'. The name comes from church singing, yet today it stretches from barbershop and doo-wop to pop groups who beatbox their own drum parts.

Which Italian instruction, literally meaning 'growing', tells musicians to get gradually louder?

Crescendo can be spelled out as 'cresc.' or drawn as a hairpin, a pair of lines that open like a wedge beneath the notes.

Which term names a short recurring theme linked to one character, like John Williams's music for Darth Vader?

Leitmotif writing is most closely linked to Richard Wagner's operas, although he did not invent the technique and never used the word for his own work.

In a standard four-part mixed choir, which voice sits directly above the bass and below the alto?

Tenor comes from the Latin tenere, 'to hold': in early part-music it was the voice that held long notes while every other part was worked out around it.

Which chord progression, built mainly on the I, IV and V chords, drives Elvis Presley's hit 'Hound Dog'?

Twelve-bar blues is one of the most prominent chord patterns in popular music. 'Hound Dog' was first recorded in 1952 by blues singer Big Mama Thornton.

Which closing section of a piece of music takes its name from the Italian word for 'tail'?

Coda sections can steal the show: the 'na-na-na' singalong that ends the Beatles' 'Hey Jude' fills more than half of the seven-minute single.

Which pitch-setting tool did John Shore, a trumpeter at the British royal court, invent in 1711?

Tuning fork prongs ring with a very pure tone, which is why the shape was chosen: nearly all of the vibration goes into one fundamental pitch.

On a staff with a G clef, the notes in the four spaces spell which word from bottom to top?

FACE only works with this clef: readers of the F clef learn their four spaces, A-C-E-G, with the phrase 'All Cows Eat Grass'.

What do British musicians call the quarter note, a name taken from the Old French for 'little hook'?

Crotchet recalls the hook that the note carried in medieval black notation, long before it took its modern plain-stemmed shape.

Which Italian word, meaning 'loud or strong', does the letter f stand for beneath a line of music?

Forte is half of the piano's full name: 'pianoforte' comes from an Italian phrase describing a harpsichord 'with soft and loud'.

In pop songwriting, which section is nicknamed the 'middle eight' because it usually lasts eight bars?

Bridge sections are the B in the classic AABA song layout, the 32-bar plan behind standards such as 'Over the Rainbow' and 'Blue Skies'.

Which two-note guitar staple, just a root and a fifth, drives the Kinks' 1964 hit 'You Really Got Me'?

Power chord playing was popularised by Link Wray, who poked a pencil through his amplifier's speaker cone to get the distorted growl of his 1958 instrumental 'Rumble'.

Which guitar notation shows where to place the fingers on the strings and frets rather than the pitches?

Tablature is no modern shortcut: it was common in the Renaissance and Baroque eras, when lute players read letters or numbers for each fret.

Which Latin word for 'work' is used to number a composer's pieces in order of publication?

Opus numbers follow publication, not composition, so music printed after a composer's death can carry a high number despite being an early work.

Which Italian marking, also the everyday word for 'sweet', tells a musician how a melody should sound?

Dolce can be pushed further to dolcissimo, 'very sweet'. Its lookalike dolente asks for a very different mood: sorrowful and plaintive.

Which Italian instruction, the opposite of accelerando, asks an ensemble to slow down gradually?

Ritardando is a gradual braking, unlike its lookalike ritenuto, which holds the music back suddenly. Confusingly, both are abbreviated 'rit.'

Which sustained, unchanging note hums beneath the melody on Highland bagpipes and the Indian tanpura?

Drone notes sound continuously beneath the tune. The Great Highland bagpipe has three pipes that do nothing else: two tenor drones and one bass drone.

Which part of a single eighth note is the stroke that hangs from the end of the stem?

Flag strokes vanish when eighth notes travel in groups: two or more are usually joined by a thick line called a beam instead.

The waltz, named from the German for 'to roll or revolve', is danced to music in which time signature?

3/4 gives each bar three quarter-note beats. The waltz began as a folk and ballroom dance in German-speaking Europe in the 18th century.

Which sign in sheet music marks a measured silence, with a different shape for each length it can last?

Rest symbols come in a full set of lengths, each one matching a note value, so the silences are counted just as strictly as the sounds.

Which word names the tone colour that lets listeners tell an oboe from a clarinet playing the same note?

Timbre is the reason two instruments playing one note at one volume still sound distinct. Many musicians pronounce the word 'TAM-ber'.

Which scale uses all twelve pitches in an octave and takes its name from the Greek word for colour?

Chromatic notes traditionally colour or embellish the major and minor scales. On a piano, this scale is simply every key played in turn.

Which Italian instruction, literally 'pinched', tells violinists to pluck the strings rather than bow them?

Pizzicato has a violent cousin: in a Bartók pizzicato the string is plucked so hard that it snaps back against the fingerboard.

Which ornament, a rapid alternation between two adjacent notes, was called a 'shake' until the early 20th century?

Trill signs are usually just the letters 'tr' above the note, sometimes followed by a wavy line when the flutter has to carry on.

Which term names the glide between pitches played by the clarinet to open Gershwin's 'Rhapsody in Blue'?

Glissando comes from the French glisser, 'to glide'. Gershwin's famous opening began as a rehearsal joke by the clarinetist Ross Gorman.

Which rare ability lets some musicians name any note they hear without a reference tone to compare it with?

Absolute pitch is widely said to occur in 1 in 10,000 people, but that may be wrong: a 2019 review found it in at least 4% of music students.

In rock and pop, which accent pattern has the snare drum hit beats two and four of a four-beat bar?

Backbeat gets a shout-out from Chuck Berry himself: 'It's got a backbeat, you can't lose it', he sings in 'Rock and Roll Music'.

Which guitarist's name do rock players attach to the jagged dominant 7♯9 chord?

Jimi Hendrix did so much to popularise the sound in rock, in songs such as 'Purple Haze', that guitarists call it the 'Hendrix chord', though jazz players had used it earlier.

In German note-naming, which letter stands for the pitch that English speakers call B natural?

H let Johann Sebastian Bach sign his surname in notes: in the German system B means B-flat, so B, A, C, H can be played as a four-note motif.

Which Italian word meaning 'half' is the m in the dynamic markings mp and mf?

Mezzo also names a voice: the mezzo-soprano, literally 'half soprano', sings in the range between the soprano and the contralto.

Which Italian term, from a phrase meaning 'stolen time', lets a soloist speed up and slow down for expression?

Rubato is forever linked with Chopin, who was said to let the melody linger behind or push ahead of the beat while the accompaniment kept time.

Which virtuosic solo passage in a concerto was traditionally improvised while the orchestra rested or held a chord?

Cadenza is Italian for cadence. In his 'Emperor' Concerto, Beethoven wrote the solo out and told the pianist not to add one of their own.

Which term for switching key mid-song covers the 'truck driver's gear change' near the end of many pop hits?

Modulation can be smooth, pivoting on a chord that both keys share, or abrupt, with the next phrase simply starting in the new key.

In guitar chord symbols such as Asus4, the letters 'sus' are short for which word?

Suspended chords replace the third with a fourth or a second above the root, and the missing third gives them an ambiguous, open sound.

Which musical form keeps returning to one main tune between contrasting episodes, in patterns such as ABACA?

Rondo movements often close a larger work: the finale of Mozart's Piano Sonata No. 11, the famous 'Rondo alla turca', is one.

Which four-chord loop, sometimes named after comedy band The Axis of Awesome, drives their medley 'Four Chords'?

I–V–vi–IV works out as C, G, A minor and F in the key of C. The medley stitches hit after hit over that one unchanging loop for comic effect.

The tongue-twisting British term 'hemidemisemiquaver' names which very short duration in American usage?

Sixty-fourth note values first appeared in the late 17th century and, a few freak cases aside, remain the shortest durations found in written music.

The opening leap of 'Here Comes the Bride', from Wagner's opera Lohengrin, is a classic example of which interval?

Perfect fourth gaps separate all but one pair of neighbouring strings on a normally tuned guitar, and sets of tom-tom drums are often spaced the same way.

The two-note shark theme in John Williams's score for Jaws rocks back and forth across which small interval?

Minor second steps are the smallest interval in everyday Western music. When Williams first played the idea for Steven Spielberg, the director laughed, thinking it was a joke.

Which jazz saxophonist gave his name to the 'changes', a chord cycle moving by major thirds, heard in 'Giant Steps'?

John Coltrane used the same cycle in 'Countdown', his reharmonised version of the jazz standard 'Tune Up'.

Which form of the minor scale traditionally uses different notes going up than it does coming down?

Melodic minor raises its sixth and seventh notes on the way up and lowers them on the way down. The rising form alone is nicknamed the 'jazz minor scale'.

Which term describes music with no home key, a label attached above all to Arnold Schoenberg and his circle?

Atonality had forerunners: Franz Liszt wrote a 'Bagatelle sans tonalité', a bagatelle without tonality, as early as 1885.

Which Baroque shorthand used numerals beside the lowest line of notes to tell keyboard players which chords to add?

Figured bass players improvised their chords from the numbers, a skill needed in almost every genre of music between about 1600 and 1750.

Which Latin word, literally '(it) is silent', tells an orchestral player to sit out an entire movement?

Tacet is the only instruction in John Cage's 4′33″: it is marked for all three movements, and the first performance passed without a note being played.

Which term names a lead-in such as the 'Happy' of 'Happy Birthday to You', sung before the first strong beat?

Anacrusis comes from the Ancient Greek for 'pushing up', and poets use the same word for extra unstressed syllables at the start of a line.

Which French composer, hailed as the 'Isaac Newton of Music', published a revolutionary Treatise on Harmony in 1722?

Rameau proposed a 'fundamental bass', an imagined line running beneath the written notes, to explain why one harmony leads to the next.

Which Russian composer built late works such as Prometheus: The Poem of Fire on a six-note 'mystic chord'?

Scriabin's 'mystic' label appears to come from his intense interest in Theosophy. He did not use the chord directly, deriving material from its transpositions.

Which medieval technique of rapidly alternating notes between voices is named from a French word for 'hiccup'?

Hocket flourished in vocal music of the 13th and early 14th centuries, and it lives on: Louis Andriessen's 'Hoketus' has two matching groups of players trade chords back and forth.