What is a cadence?

A cadence is a series of notes and/or chords which indicate the end of a phrase or section in a piece of music. There are many different kinds of phrases but the most common are perfect, imperfect and playgal cadences. A cadence often go to chord I - the root. A perfect cadence, for example, goes from Chord V to Chord I. A playgal cadence is Chord IV to Chord I. An imperfect cadence, as the name suggests, doesn't follow the rule and is any chord (often VI) to Chord V. This cadence doesn't have the same finished sound as the other cadences and can be tricky to hear.