It is not to be called the "sonata form," but the "sonata-allegro form." It is to one movement only, generally the first one, which is (or was) very commonly an _allegro_ tempo in the sonata and symphony, that the present design refers; and its name, sonata-allegro, is derived from that old historic species of the sonata which consisted originally of but one movement, generally an _allegro_.
THE SONATA-ALLEGRO FORM .-- As distinguished from the sonatine-form, with its two Divisions, this larger species, based upon precisely the same structural idea, has _three Divisions_,--the Exposition, a middle Division called the Development (growing out of the brief interlude of the sonatine-form), and the Recapitulation.

The diagram (the keys of which correspond to the plan of Beethoven, op.

14, No.

2, first movement) is as follows: Exposition.

Middle Div.