Drop2

Glossary

Jazz guitar terms, defined

By Oliver Duschka, the developer of Drop2

The words that turn up on this site, in a method book, and on a bandstand — each one answered in a sentence or two. Where the thing can be seen on the neck or heard, the definition says which page to go to.

Chords: what they are made of

Jazz chords are four notes deep before anything is added to them. These are the words for the notes themselves — which ones matter, which ones can go, and what each combination is called.

Chord quality

chord type

A chord's quality is what kind of chord it is, independent of its root — major seventh, dominant seventh, minor seventh, half-diminished, diminished, minor-major. Quality lives almost entirely in the third and the seventh: change those two notes and Cmaj7 becomes C7, then Cm7. Six qualities account for most of the chord symbols in a standard — maj7, 7, m7, m7♭5, dim7 and mMaj7 — and those are the six on the voicing explorer.

Guide tones

guide tone line

The guide tones of a seventh chord are its third and its seventh — the two notes that decide whether it sounds major, minor or dominant. In G7 they are B and F. Drop the root and the fifth and the chord still says what it is; drop a guide tone and it stops being that chord, which is why these two are what a line aims at and what carries a progression from one chord to the next. The guide-tones article plays them alone.

Chord tone

A chord tone is one of the notes the chord is built from — its root, third, fifth or seventh. Every other note is passing through. Where the chord tones fall in a solo is most of the difference between a line that sounds like the harmony and one that sounds like a scale.

Tritone

augmented fourth · diminished fifth

A tritone is an interval of six semitones — three whole tones, exactly half an octave. Every dominant seventh chord contains one, between its third and its seventh (in G7, B and F), and that interval is the tension the chord resolves. It is also symmetrical: turn a tritone upside down and it is still a tritone, which is what makes the tritone substitution work.

Extension

9th · 11th · 13th · color tones

Extensions are the notes stacked above the seventh — the 9th, 11th and 13th, which are the 2nd, 4th and 6th an octave up. They color a chord without changing its job: G13 pulls exactly where G7 pulls. On four strings something has to leave to make room, which is the whole subject of chord extensions on guitar.

Altered dominant

alterations · ♭9 · ♯9 · ♯11 · ♭13

An altered dominant is a dominant seventh chord with a raised or lowered fifth or ninth — ♭9, ♯9, ♯11, ♭13, in any combination. Each alteration brings in a note from outside the key, which sharpens the pull toward the chord that follows, so they cluster on the V chord and especially on the V of a minor key. On the fretboard an alteration is usually one finger moving one fret: G13 becomes G13♭9 without the hand going anywhere.

Sixth chord

C6 · major 6 · m6

A sixth chord replaces the seventh with the sixth: C6 is C–E–G–A. Guitarists reach for it where a major seventh would be too sweet or would collide with the melody, and it is the standard swap when the root ends up as the top note of a drop-2 maj7 shape — there the seventh is the lowest voice, a minor ninth under that root, which is the one interval that grates. That is why every third-inversion maj7 on this site is drawn and named as a 6.

Half-diminished

m7♭5 · ø · minor seven flat five

A half-diminished chord is a minor seventh chord with its fifth flattened, written m7♭5 or ø: Dm7♭5 is D–F–A♭–C. It is the ii of a minor key, which is where most guitarists meet it — at the front of a minor ii–V–i. It also holds exactly the notes of a minor sixth chord built a minor third above it (Dm7♭5 and Fm6 are the same four notes), so one grip answers to both names.

Diminished seventh

dim7 · °7

A diminished seventh chord stacks four notes in minor thirds — C, E♭, G♭, B♭♭, that last one sounding as A. The stack is symmetrical, so any of the four notes can be called the root: there are only three different diminished sevenths in all, and each shape repeats every three frets. In a tune it usually turns up as a passing chord shifting the bass a half step, as the ♯iv° does in bar 6 of rhythm changes.

Voicings: how a chord sits on the guitar

A chord symbol says which notes. A voicing says where they are, in which octave, on which strings — and on the guitar that choice is most of the sound.

Voicing

A voicing is one particular arrangement of a chord: which of its notes you play, in which octave, and in what order from the bottom up. The symbol Cmaj7 names four notes and stops there; the voicing decides they come out as G–C–E–B on four adjacent strings. Two guitarists reading the same chart are almost always playing different voicings, and that is where most of a comping sound lives.

Close position

closed voicing

A chord is in close position when its notes are packed as tightly as they go — each one a third above the last, the whole chord inside a single octave. Cmaj7 in close position is C–E–G–B. Under a pianist's hand that is one comfortable grip; on a fretboard it forces thirds onto neighboring strings, and several close shapes cannot be fingered at all. Opening one up is what the drop does.

Drop 2

drop-2 voicing · drop two

A drop-2 voicing takes a four-note chord in close position and lowers the second voice from the top by an octave. Cmaj7 stacked close is C–E–G–B; drop the G and it becomes G–C–E–B — the same four notes, one per string, sitting under one hand. It is the everyday comping voicing of jazz guitar, and the move Drop2 is named after: the full article builds it, and the explorer plays every one of them.

Drop 3

drop-3 voicing · drop three

A drop-3 voicing does the same thing to the third voice from the top, which leaves a wider gap between the bass note and the rest of the chord. On the guitar that gap is a skipped string: the root on the sixth string, nothing on the fifth, the other three notes on D, G and B. It sounds bigger and leaves more room underneath, which is why solo and duo players reach for it — the drop-3 article has the four inversions.

Inversion

root position · 1st, 2nd, 3rd inversion

A chord is inverted when a note other than its root is the lowest one sounding. A four-note chord has four positions — root position and first, second and third inversion, named for whether the root, third, fifth or seventh is on the bottom. On the guitar each one is a separate grip in a separate part of the neck, and picking between them is what voice leading does.

String set

top 4 · mid 4 · bottom 4

A string set is the group of adjacent strings a voicing sits on. Four-note chords on a six-string guitar have three sets to choose from: the top four (D–G–B–e), the middle four (A–D–G–B) and the bottom four (E–A–D–G). The same chord in the same inversion is a noticeably different sound on each — the high set cuts through a band, the low set thickens and can crowd the bass. The explorer switches between them.

Top note

melody note · lead voice

The top note is the highest-sounding note of a voicing — the one a listener follows as the melody. Choosing an inversion is mostly choosing a top note, which is why every diagram on this site names it in its caption: Cmaj7 · top note G · 1st inversion. Comping behind a singer is largely the art of deciding what your top note is doing.

Shell voicing

shell chord · three-note voicing

A shell voicing is a three-note chord — root, third and seventh, with the fifth left out. It is the smallest grip that still names both the chord and its quality, it moves around the neck easily, and it stays out of the bass player's way. Shells sit exactly between two-note guide tones and four-note drop-2 shapes: the article plays the staircase.

Rootless voicing

A rootless voicing leaves the root out and lets the bass supply it. With four strings and a chord that wants a ninth or a thirteenth, something has to go, and the root goes first — it is the one note the bass is certain to play. Dm9 voiced F–A–C–E is the clearest case: a Dm7 that traded its root for the ninth, and still sounds like Dm9 the moment a bass note lands under it.

Voice leading

Voice leading is choosing each chord's shape so that its notes travel as little as possible from the chord before — a half step where possible, no step at all where the note is shared. Played that way a progression stops sounding like a series of grips and starts sounding like one thing moving. It is also less work: the hand stays in one window of the neck. The article shows it on a ii–V–I, and the practice pages voice-lead every progression they loop.

Comping

accompanying

Comping is playing the chords behind a soloist or a singer — short for accompanying. It is as much rhythm as harmony: placing chords off the beat, leaving space, answering a phrase instead of covering it. Drop-2 voicings are the vocabulary most guitarists comp with, which is why they are the center of this site.

Chord melody

Chord melody is playing a tune's melody and its harmony at the same time, with the melody as the top note of every chord. It is the practical reason inversions are worth learning: four inversions on each string set mean any chord tone can be put on top, so a melody can be harmonized note by note without the hand jumping around the neck.

CAGED

CAGED is a system that maps the neck with five movable shapes taken from the open C, A, G, E and D chords. As a map it works well — it answers "where am I" and frames scales and arpeggios around shapes you already know. As a jazz chord vocabulary it fits poorly, because those grips are six-string, root-heavy and doubled where jazz comps four notes, often rootless and voice-led: the honest version of that answer.

Progressions: how chords move

Chords are only interesting in sequence. These are the movements that turn up in tune after tune, and the moves that change them.

The changes

chord changes · playing the changes

The changes are a tune's chord progression — the sequence the rhythm section plays and the soloist improvises over. "Playing the changes" means the line follows the harmony as it moves rather than sitting in one scale over the whole thing. For a jazz musician a tune's identity is usually its changes and its form, not its lyric.

Roman numerals

scale degrees · I–vi–ii–V

Roman numerals name a chord by its position in the key rather than by its letter — I on the first degree, ii on the second, V on the fifth, upper case for major and lower case for minor. Numbered that way a progression is key-independent: ii–V–I is Dm7–G7–Cmaj7 in C and Fm7–B♭7–E♭maj7 in E♭. The charts on the practice pages carry both, because twelve keys are one progression twelve times.

Diatonic

Diatonic means belonging to the key — built only from the seven notes of its scale, with no accidentals. The diatonic seventh chords of C major are Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7♭5, and a progression made only from those stays inside the key. Most of what makes jazz harmony interesting is the moments it steps outside, starting with the secondary dominant.

ii–V–I

two five one · 2-5-1

The ii–V–I is the cadence most of jazz is built from: the minor seventh chord on the second degree, the dominant on the fifth, resolving to the tonic. In C that is Dm7–G7–Cmaj7 — a chord that leans, a chord that pulls, a chord that lands. It appears in nearly every standard, often several times and in several keys, so it is the first thing worth knowing everywhere on the neck: the major one, the minor one.

Turnaround

A turnaround is the short passage at the end of a chorus whose job is to hand the tune back to bar one. The common one is I–VI–ii–V — in C, Cmaj7–A7–Dm7–G7 — four bars that deliberately end unresolved, so the top of the form arrives as an answer. The practice page loops it in every key.

Secondary dominant

V7/ii · V of V

A secondary dominant is a dominant seventh chord aimed at a chord other than the tonic — the V of something else, written V7/ii or V7/V. In C, turning Am7 into A7 makes it the dominant of Dm7, and it costs exactly one note: A7's C♯ where Am7 had a C. It is the cheapest way to make a diatonic progression lean, and the first move in reharmonizing anything.

Tritone substitution

tritone sub · ♭II7

A tritone substitution replaces a dominant chord with the dominant seventh a tritone away: G7 becomes D♭7. The two share their tritone — G7's B and F are D♭7's C♭ and F, the same two notes with their roles swapped — so the tension is identical and mainly the bass note changes, which lets the bass walk down by half steps (D–D♭–C instead of D–G–C). Hear it against the original.

Reharmonization

reharm

Reharmonizing means keeping a melody and changing the chords underneath it. The reliable moves are small: make a resting chord dominant so it points somewhere, insert its ii in front of it, or swap a dominant for its tritone substitute. Every one of them replaces a chord that is sitting still with one that is leaning — three of them, in order.

Tunes: the shapes they come in

The vocabulary of a session — what people mean when they call a tune, count it off, and take turns.

Standard

A standard is a tune the jazz community has agreed to know — the shared repertoire you can call at a session without handing anyone music. Most come from Broadway and film songs written between the 1920s and the 1950s, plus the jazz originals that stuck. Learning one means learning its form and its changes, not only its melody.

Form

AABA · 32-bar form

A tune's form is the shape it repeats: how many bars, divided into which sections. Most standards are 32 bars as AABA or ABAC; a blues is 12. Everything that happens — the melody, every solo, the ending — runs around that same shape, which is why musicians count a performance in choruses rather than in minutes.

The head is a tune's written melody, played at the beginning and again at the end with the solos in between — "head in, head out". Calling a tune at a session means everyone plays the head, then takes turns over its changes, then plays it once more to finish.

Chorus

A chorus is one complete pass through the form, from bar one to the last bar. In jazz the word does not mean the catchy repeated part of a song: a soloist who takes three choruses plays through the whole tune three times.

Jazz blues

The jazz blues is the twelve-bar blues with jazz harmony in it: the familiar I7–IV7 opening, but bars 8 to 10 become a VI7–ii7–V7 approach where a plain blues plays I7–V7–IV7. In F that is D7–Gm7–C7 instead of F7–C7–B♭7 — one turnaround's worth of change, and the form starts moving in ii–Vs. It is the first form most jazz musicians can play in every key, and the one most likely to be called at a session: both versions loop side by side.

Rhythm changes

Rhythm changes are the chords of Gershwin's "I Got Rhythm" (1930), a 32-bar AABA form that is jazz's second vehicle after the blues. The A section is eight bars at two chords a bar, mostly a turnaround going round and round; the bridge is four dominant chords, two bars each, climbing in fourths. A chord progression is not protected the way a melody is, which is part of why so many bebop heads were written over these ones: the A section and the bridge.

Playing it

Words for the rhythm, the bass line, the solo, and the practice that gets you there.

Swing

swung eighths · swing feel

Swung eighths are played long-short instead of evenly: the beat divides roughly two to one, so the offbeat lands late — about two thirds of the way through the beat, which is the value the band on this site plays. It is a feel rather than a rhythm that can be written down exactly, and it straightens toward even eighths as the tempo climbs.

Walking bass

A walking bass line is one note per beat, moving mostly by step, that joins each chord's root to the next. The standard recipe over a bar of one chord is root, third, fifth, then a chromatic approach note a half step from the root that is coming — which is exactly how the bass on the practice pages is built. Its job is to make the harmony audible and the time unmistakable at once.

Line

jazz line · lick

A line is a phrase of single notes — the jazz word both for what you play when you solo and for the vocabulary you collect to play it with. What makes a line jazz is not the notes in it but where they land against the chords going by underneath.

Approach note

chromatic approach

An approach note is a note played immediately before a target, usually a half step above or below it and usually not in the chord. It works because the ear hears it as motion toward something rather than as a wrong note. Walking bass lines are built out of them, and so is most bebop phrasing.

Target note

A target note is the note a phrase is aimed at — most often a guide tone of the chord you are arriving on, landing on a strong beat. Choosing targets first and filling in afterwards is the quickest cure for solos that sound like scales. The app's Lines trainer names the target for each bar and checks by ear whether you hit it (part of Premium).

Spaced repetition

SRS · review scheduling

Spaced repetition means reviewing something just before you would have forgotten it, with the gap widening every time it comes back correct. For a guitarist it is the difference between having played twelve keys once and knowing twelve keys — and it is what makes a short daily session compound. The twenty-minute routine is built on it.

From the page to the fretboard

Definitions are the cheap part. A word like inversion becomes useful at the moment the four shapes are under your fingers and something tells you whether what you played is what you meant: the Drop2 app teaches the drop-2 voicings named here — every quality, inversion and string set — and listens through the microphone while you play them back. If you would rather read than drill, the articles take these terms one at a time, and the practice pages put them in motion with a band behind them.

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