Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. Also called (i) first-movement Form. (2) Symphony Form, (3) Sonata Allegro Form, (all so named because the First Movements of Sonatas, Symphonies, etc., are most frequently constructed on this particular design), and (4) formerly called Binary Form, because the movement is founded on two subjects. Sonata Form consists of three parts (i) A. Enunciation or Exposition.