Толковый словарь английского языка Oxford English Reference - sonata

n. a composition for one instrument or two (one usu. being a piano accompaniment), usu. in several movements with one (esp. the first) or more in sonata form. Phrases and idioms sonata form a type of composition in three sections (exposition, development, and recapitulation) in which two themes (or subjects) are explored according to set key relationships. Etymology: It., = sounded (orig. as distinct from sung): fem. past part. of sonare sound