# Seventh Chords

The name gives it away: seventh chords chords must have some kind of seventh in them. Indeed, they are triads bringing their plus-one. Here are some examples with root $G$:

X:1 L:1/4 K: C "GΔ"[GBd^f] | "Gm7"[G_Bdf] | "G7"[GBdf] | "Go7"[G_B_d_f] | "Gø"[G_B_df] ||

The first of these examples, the $G^\triangle$ is a G major 7. In this chord symbol, $G$ signifies that the base triad is G major, and the $\triangle$ specifies the character of the seventh -- this one is a major seventh, as opposed to a minor seventh. Read 1-intervals{.interpreted-text role="doc"} first if you don't know what this means. Here are three examples of major seventh chords:

\begin{aligned} G^\triangle &= \left\{ \underbrace{g, b, d}_{G \text{ major triad}} +\quad \underbrace{f\sharp}_{\text{major seventh}} \right\}\\ D^\triangle &= \left\{ \underbrace{d, f\sharp, a}_{D \text{ major triad}} +\quad \underbrace{c\sharp}_{\text{major seventh}} \right\}\\ B\flat^\triangle &= \left\{ \underbrace{b\flat, d, f}_{B\flat \text{ major triad}} +\quad \underbrace{a}_{\text{major seventh}} \right\}\\ \end{aligned}

The same principle applies to the other seventh chords. A $\minor7$-chord is made up out of a minor triad and a minor seventh.

\begin{aligned} G\minor7 &= \left\{ \underbrace{g, b\flat, d}_{G \text{ minor triad}} +\quad \underbrace{f}_{\text{minor seventh}}\right\}\\ D\minor7 &= \left\{ \underbrace{d, f, a}_{D \text{ minor triad}} +\quad \underbrace{c}_{\text{minor seventh}}\right\}\\ B\flat\minor7 &= \left\{ \underbrace{b\flat, d\flat, f}_{B\flat\text{ minor triad}} +\quad \underbrace{a\flat}_{\text{minor seventh}}\right\} \end{aligned}

Here are some examples of $7$-chords, known as dominant chords for reasons that will become clear in the next post about chord progressions.

\begin{aligned} G7 &= \left\{ \underbrace{g, b, d}_{G \text{ minor triad}} +\quad \underbrace{f}_{\text{minor seventh}}\right\}\\ D7 &= \left\{ \underbrace{d, f\sharp, a}_{D \text{ minor triad}} +\quad \underbrace{c}_{\text{minor seventh}}\right\}\\ B\flat7 &= \left\{ \underbrace{b\flat, d, f}_{B\flat\text{ minor triad}} +\quad \underbrace{a\flat}_{\text{minor seventh}}\right\} \end{aligned}

You should be able to assemble the other seventh chords yourself, based on the information in this table:

Major seventh$C^\triangle$MajorMajor
Dominant$C7$MajorMinor
Minor seventh$C\minor7$MinorMinor
Minor major$C_\minor^\triangle$MinorMajor
Diminished$C^o$DiminishedDiminished (enharmonically equivalent to $M6$)
Half-diminished$C\text{\o}$DiminishedMinor