art form vs sonata form

art form and sonata form both are nouns.

Word	Noun	Adjective	Verb	Adverb
art form	Yes	No	No	No
sonata form	Yes	No	No	No

As nouns, sonata form is a hyponym of art form; that is, sonata form is a word with a more specific, narrower meaning than art form:

art form: (architecture) a form of artistic expression (such as writing or painting or architecture)
sonata form: the form of a movement, which consists of exposition and development and recapitulation

Other hyponyms of art form include architectural style, style of architecture, type of architecture.

art form (noun)	sonata form (noun)
(architecture) a form of artistic expression (such as writing or painting or architecture)	the form of a movement, which consists of exposition and development and recapitulation