Musical form. To quote Fr. Blume in the German music encyclopedia Musik in Geschichte und Gegenwart, article on form, column 525: Types of musical composition which are connected to a certain purpose, certain types of usage, certain texts or certain performance practices (e.g. motet, opera, concerto grosso, string quartet), which, however, do not necessarily have to be based on a certain form (in the specialized sense of the word). Characteristic of the genre is that it remains true to its intended use, its category of literary texts, its typical instrumentation, even if it changes its empirical form within these limits.