We’ve been studying harmony—triads and chords. A cadence is a harmonic arrival point, a harmonic moment of stasis. A cadence can be compared to a comma or period in written language—the ear gets a moment to process a short passage of music, then the music continues. We will differentiate between four basic cadences now, adding more specificity in a later chapter.

1. Authentic Cadence (AC): a phrase ending with the chords $\left.\text{V}\right.$–$\left.\text{I}\right.$

2. Plagal Cadence (PC): a phrase ending with the chords $\left.\text{IV}\right.$–$\left.\text{I}\right.$

3. Deceptive Cadence (DC): a phrase ending with the chords $\left.\text{V}\right.$–$\left.\text{vi}\right.$

4. Half Cadence (HC): a phrase ending on the $\left.\text{V}\right.$ chord

In the example above, the notes surrounded by parentheses are non–chord tones, which will be studied later. Also, there are seventh chords in this example, which we will study in the next chapter.

Here is another example ending with an authentic cadence.

Here are examples with plagal cadences.

A deceptive cadence means $\left.\text{V}\right.$ did not go to $\left.\text{I}\right.$. This means that “$\left.\text{V}\right.$ to not–$\left.\text{I}\right.$” is technically a more correct description for a deceptive cadence than $\left.\text{V}\right.$–$\left.\text{vi}\right.$, which is the most common realization of “$\left.\text{V}\right.$ to not–$\left.\text{I}\right.$.”
In the example below, $\left.\text{V}\right.$ goes to $\left.\text{IV}\middle/\text{3rd}\right.$.
You may encounter chords with no thirds in rock and pop music. If you encounter a chord that has only a root and fifth, label it with a “5” after the root in lead sheet labeling (e.g., $\left.\text{B}^{5}\right.$, as in the next example).