A Phrygian Half Cadence is a specific type of musical cadence that creates a sense of tension and expectation, typically resolving to the tonic chord. This cadence occurs when the subdominant chord (IV) is followed by the dominant chord (V), with the notable use of the flat 2nd scale degree in the melody. It is characterized by its unique sound, often associated with the Phrygian mode, and serves as an effective transition to establish a musical idea.