Cadence
A cadence is the chord sequence that ends a musical sentence. The most common cadence, I–IV–V–I (C–F–G–C in C major), sounds finished, like a full stop at the end of a sentence.
Chords make musical sentences, and a sentence needs an ending. Tonic (I), subdominant (IV), dominant (V) and tonic again: home, a step away, further away, and home. When the last chord is the tonic, the ear hears: finished.
The ending can be made firmer: in place of V, take the dominant seventh V7. Its F falls to E and its B rises to C – two notes lead straight into the tonic, and the ending is as final as it gets. And if you stop on V without going on to I? The sentence hangs in the air, like a question. Such an ending is called a half cadence; it suits the middle of a phrase, not the end of a piece.
In a cadence the chords are often played in inversions so the hand hardly moves: C as C–E–G, F as C–F–A, G7 as B–D–F–G. In songs you hear the cadence at the end of a verse or chorus; in chord letters it looks like … G7 C.
What it sounds like
A full cadence sounds like a full stop: the tension builds to V7 and dissolves in the tonic. A half cadence, stopping on V, sounds like a question – the ear waits for more.
Where it is taught: the studio’s interactive textbook, chapter 11, “Triad inversions and the dominant seventh”.