EXPRESSIVENESS • DICCIONARIO INGLES.COM • Definition of Expressiveness

... real life our sequent clusters of emotional states are in general determined by their association with our sequent groups of intellectual ideas, it would seem that music, regarded as an exponent of psychical life, reaches its fullest expressiveness when the sequence of the moods which it incarnates in sound is determined by some sequence of ideas, such as is furnished by the words of a libretto. Not that the words should have predominance over the music, or even coequal sway with it, but that they should serve to give direction to the succession ...

— The Unseen World and Other Essays • John Fiske