Romantic Movement vs idiom

Romantic Movement and idiom both are nouns.

Word	Noun	Adjective	Verb	Adverb
Romantic Movement	Yes	No	No	No
idiom	Yes	No	No	No

As nouns, idiom is a hypernym of Romantic Movement; that is, idiom is a word with a broader meaning than Romantic Movement:

Romantic Movement: a movement in literature and art during the late 18th and early 19th centuries that celebrated nature rather than civilization
idiom: the style of a particular artist or school or movement

Other hypernyms of Romantic Movement include artistic style, arts, humanistic discipline, humanities, liberal arts.

Romantic Movement (noun)	idiom (noun)
a movement in literature and art during the late 18th and early 19th centuries that celebrated nature rather than civilization	the style of a particular artist or school or movement
	the usage or vocabulary that is characteristic of a specific group of people
	an expression whose meanings cannot be inferred from the meanings of the words that make it up
	a manner of speaking that is natural to native speakers of a language