borrowed chord
A chord taken from the parallel key or mode and used in the current tonal context
In Depth
A borrowed chord is any chord that does not belong to the prevailing key but is imported from a parallel mode. In C major, for example, the chords Fm, A♭, B♭, and E♭ are all borrowed from C minor. The minor iv chord is the most frequently borrowed harmony in popular music. Borrowed chords add colour without requiring modulation because listeners perceive them as inflections of the home key rather than departures from it.
The Radiohead song Creep features one of the most recognisable borrowed chords in rock: the III chord (G–B♭–D in the context of G major) drawn from the parallel minor.