Definition of Sonata?

[Bachvein]

My question is what makes a Sonata.
Most of them follow the typical Allegro-Andante-Allegro structure.

But inside each movement they are supposed to follow a certain body, which is roughly Exposition, Development and Recapitulation.
But if the movements didn't follow that pattern, if they were instead themes and variations, would it still be called a Sonata?

Are these terms very strict in the music world? or is a Sonata simply something that is "sounded"- played with a plain overall structure?

Thanks

[steltz]

Not at all, because the term changes throughout history. The Exposition, Development and Recapitulation you describe was only fully developed in the Classical period, and would only apply to the first movement, though exceptions do occur. But most importantly, the earliest sonatas were one-movement pieces, and good examples of these would be the Scarlatti sonatas.

VERY roughly, the word sonata originally meant something sounded (i.e. sonare) as opposed to sung, so any rules as to how sonatas were structured developed as time went on, and then, as with all history, people get tired of the strictness of the "rules" and then break them. So one movement becomes three, and then it becomes almost anything as the freedom of the late-19th and early 20th Century gets into full swing.

Theme and variation form can be used in an individual movement of a sonata (just as Beethoven unusually used it in a slow movement of a symphony, can't remember which one now), but I can't think of any pieces off the top of my head where the whole piece is a theme and variations form but is still titled a "sonata".

I think the short answer is that there is no definition that covers all of them, and what definitions there are depend heavily on period.

[sbeckmesser]

I recommend reading Sonata Forms by the late, great Charles Rosen, which discusses various structures for sonata movements. It contains the great quote: "Sonatas are like chimpanzees."

[Bachvein]

thank you for your help