A borrowed chord is a chord borrowed from the parallel key. If the root of the borrowed chord is not in the original key, then they are named by the accidental. For instance, in major, a chord borrowed from the parallel minor's sixth degree is a "flat six chord" written ♭VI (or bVI if the flat is not available in the font). Borrowed chords are an example of mode mixture. In music and music theory, a chord (from the middle English cord, short for accord) is three or more different notes or pitches sounding simultaneously, or nearly simultaneously, over a period of time. ... In music, the parallel minor of a particular major key (or the parallel major of a minor key) is the key which has the same tonic and a different key signature, as opposed to relative minor (or major, respectively). ... The root (basse fondamentale) of a chord is the note upon which that chord is perceived or labelled as built or centered, the root of a chord in root position or normal form. ... An accidental is a musical notation symbol used to raise or lower the pitch of a note from that indicated by the key signature. ... Badge of rank of a Major in the British Army. ... In music mode mixture is the use of pitches or chords from the parallel minor or major scale or key of a piece or section. ...

In the Baroque, Classical and Romantic eras, six chords borrowed from the parallel minor key are most commonly found (shown here in C major): Baroque music is Western classical music from the Baroque era, after the Renaissance music era and before the Classical music era proper. ... The Classical period in Western music occurred in a large part of the 18th century, and into the early 19th century. ... Romantic music is defined as the period of European classical music that runs roughly from the early 1800s to the first decade of the 20th century, as well as music written according to the norms and styles of that period. ...

• Diminished Supertonic Triad (ii°): D, F, A flat
• Half-Diminished Supertonic Seventh (ii^Ø7): D, F, A flat, C
• Major Triad on the Lowered Third Scale Degree, or "Flat Three" (♭III): E flat, G, B flat
• Minor Subdominant (iv): F, A flat, C
• Major Triad on the Lowered Sixth Scale Degree, or "Flat Six" (♭VI): A flat, C, E flat
• Fully Diminished Leading-Tone Seventh (vii°⁷): B, D, F, A flat

The following three chords are also found in Romantic era, albeit rarely:

• Minor Subdominant Seventh (iv^♭7): F, A flat, C, E flat
• Major-Minor Subdominant Seventh (IV^♭7): F, A, C, E flat
• Minor Dominant Ninth (V^♭9): G, B, D, F, A flat

The Major-Minor Subdominant Seventh, which contains an A natural, is borrowed from the parallel ascending melodic minor scale. A minor scale in musical theory can be viewed as the sixth mode of the major scale. ...

Borrowing from a parallel major key is generally limited in western music to ending a minor piece on a major tonic triad, a chord which is then called a Picardy third. An example of mode mixture, the harmonic device of a picardy third (Tierce de Picardie) is the use of raised third in the final tonic chord of a musical composition or section in minor, the use of which originated in the 16th century and the Baroque era and was common...