tierce de Picardie

In music, the major third introduced into the final chord of a composition in a minor key. The major third corresponds to a natural harmonic, the tierce, but the minor third does not; it was therefore for a long time considered an unsatisfactory ingredient in a concluding chord, if not an actual dissonance, for which reason the tierce de Picardie was often substituted. The origin of the name is not known.