noun.
In music, in the seventeenth and eighteenth centuries, any composition for instruments: opposed to cantata.
noun.
In recent music, an instrumental work, especially for the pianoforte, made up of three or four movements in contrasted rhythms but related keys, one or more of which are written in sonata form.
noun.
exposition, containing the first subject, followed by the second, properly in the key of the dominant or in the relative major (if the first be minor);
noun.
development or working out, consisting of a somewhat free treatment of the two subjects or parts of them, either singly or in conjunction;
noun.
restatement containing the two subjects in succession, both in the original key, with a conclusion. The succession of sections and the relations of keys are open to considerable variation, and episodes often occur. The sonata form is distinctive of at least one movement of a sonata or symphony, and usually of the first and last; it also appears in many overtures.