Definition from Wiktionary, the free dictionary
- (music) A type of imperfect cadence frequently found in Baroque compositions. The gesture consists of a IV6-V final cadence in the minor mode at the end of a slow movement or slow introduction. It implies that a fast movement is to follow without pause, generally in the same key.
Usage notes 
- The term Phrygian is, strictly speaking, inaccurate: the cadence does not represent or belong to the Phrygian mode. The name presumably arose because of the half-step movement (flat submediant degree to dominant degree) found in the bass, which to an extent resembles the II-I cadence of the Fifteenth century.