Harmony and Voice Leading IV: Secondary Function

Tonic (I)

The primary “home” chord/scale degree in a key; the main point of stability in tonal music.

Home key

The main key of a piece or passage—the key that governs the overall harmonic context.

Secondary function

Harmony that acts like dominant (or leading-tone) function of a scale degree other than the main tonic, creating extra pull without changing the global key.

Secondary key

A temporarily suggested key that is not the piece’s primary key, used for brief tension or contrast.

Temporary tonic

A note/chord that momentarily sounds like a tonal center (“home base”) during a tonicization.

Tonicization

The process of making a diatonic chord (e.g., ii, V, vi) sound temporarily like a tonic by preceding it with applied dominant/leading-tone harmony.

Directed motion

The sense of harmonic movement in tonal music driven by tension/release and instability/stability (often intensified by secondary function).

Extra dominant-to-tonic energy

The increased sense of pull created when a secondary dominant or leading-tone chord aims at a chord other than I.

Chromatic accidental (in secondary function)

A non-diatonic pitch often introduced to create a leading tone to a temporary tonic (e.g., F♯ in C major aiming to G).

Modulation

A real change of key, typically confirmed by cadence and sustained harmonic support so the new tonic feels “in force.”

Cadence (as key confirmation)

A closing progression (often authentic) that can confirm a new key during modulation.

Secondary dominant

A dominant-function chord (usually major triad or dominant seventh) that tonicizes a diatonic chord by acting as its V.

Secondary leading-tone chord

A diminished leading-tone chord (triad or seventh) that tonicizes a diatonic chord by acting as its vii° (or viiø7/vii°7).

Applied chord

Another name for a secondary dominant or secondary leading-tone chord; it “applies” dominant/leading-tone function to a target chord.

Closely related keys

Keys sharing many notes with the home key; typically differ by one accidental and are adjacent on the circle of fifths.

Circle of fifths

A representation of key relationships; adjacent keys differ by one sharp/flat and are often the most closely related.

Target chord (x)

The chord being tonicized; it appears after the slash in a secondary-function label (e.g., V/ii targets ii).

V/x

Roman-numeral label meaning “dominant of x,” where x is the chord being tonicized (the target).

V7/x

A dominant seventh chord that functions as the dominant of the target chord x, intensifying the resolution.

Leading tone (temporary key)

The note a half step below the temporary tonic that strongly resolves upward to that tonic.

Chordal seventh (in V7/x)

The 7th of a dominant seventh chord; a tendency tone that typically resolves downward by step.

Tendency tones

Notes with strong expected resolutions (especially leading tones resolving up and chordal sevenths resolving down).

Resolution (in secondary function)

The expected voice-leading motion of tendency tones toward the target chord that makes an applied chord sound convincing.

Regular resolution

Resolution where the leading tone resolves upward to the expected tonic (stability/finality).

Irregular resolution

Resolution where the leading tone resolves downward (not to the expected tonic), increasing tension/instability.

Deceptive resolution

Resolution where an expected tonic arrival is avoided and another chord occurs instead, creating surprise (can be understood within the temporary key area).

Inversion (applied chords)

A chord position with a chord tone other than the root in the bass; applied chords appear in all inversions.

Figured bass (with applied chords)

Symbols indicating chord inversion/spacing; used alongside secondary-function labels (e.g., V6/V, V4/3/V).

V6/V

A first-inversion secondary dominant: a V/V chord in first inversion (in C major, a D major chord with F♯ in the bass).

V4/3/V

A second-inversion applied dominant seventh: V7/V in 4/3 position (in C major, D7 with A in the bass).

Chord symbol suffix

Added notation in lead-sheet symbols indicating chord type/quality (e.g., “7” for dominant seventh, “maj7” for major seventh).

Roman numeral analysis

A functional notation system labeling chords by scale degree and quality (including secondary-function forms like V/ii).

Voice leading (secondary function)

How individual voices move between chords; crucial for making applied chords sound inevitable and for earning points on AP-style writing.

Doubling (in SATB)

Writing the same chord tone in more than one voice; must be managed carefully in applied chords to avoid errors.

Omitting the fifth (in dominant-type writing)

A common option in four-part writing: the fifth of a secondary dominant can be omitted if needed to avoid voice-leading problems.

vii°/x

A diminished triad built on the leading tone of the temporary key that resolves to the target chord x.

viiø7/x

A half-diminished leading-tone seventh chord applied to x (minor seventh above the chord root).

vii°7/x

A fully diminished leading-tone seventh chord applied to x (diminished seventh above the chord root).

Diminished triad

A triad built in minor thirds containing a diminished fifth; inherently unstable and strongly directed to resolution.

Half-diminished seventh chord

A leading-tone seventh chord quality with a diminished triad plus a minor seventh above the root (viiø7).

Fully diminished seventh chord

A leading-tone seventh chord quality with a diminished triad plus a diminished seventh above the root (vii°7).

Harmonic minor (leading-tone source)

Minor-mode practice of raising scale degree 7 to create a strong leading tone; affects spelling/quality of applied chords to minor targets.

Enharmonic spelling (functional importance)

Choosing note spellings that show function (e.g., F♯ not G♭ in C major for V/V), since spelling implies harmonic meaning.

Slash in AP secondary-function notation

The slash indicates the target chord being tonicized (e.g., V/vi = “dominant of vi”).

Slash chord (lead-sheet usage)

A chord symbol like C7/F meaning “C7 with F in the bass”; not the same as AP secondary-function slash labels.

Cadential 6/4

A dominant embellishment where I6/4 resolves to V; it is not an applied dominant (e.g., C–E–G over G resolving to G–B–D).

Expanded predominant (with applied chords)

A predominant area intensified by tonicizing ii (e.g., I → V/ii → ii → V → I), adding strong forward drive.

Circle-of-fifths sequence (chain of applied dominants)

Progression moving by descending fifths/ascending fourths, often using multiple secondary dominants to “lock in” each next chord (e.g., V/vi → vi → V/ii → ii → V/V → V → I).

Diatonic chord

A chord built from notes within the home key’s scale (common targets of tonicization include ii, V, vi, sometimes iii).

Mode mixture (borrowed chord)

Using chords/tones borrowed from the parallel major/minor; a potential source of chromatic notes that is distinct from secondary function.