fluegelhorn vs brass instrument

fluegelhorn and brass instrument both are nouns.

Word	Noun	Adjective	Verb	Adverb
fluegelhorn	Yes	No	No	No
brass instrument	Yes	No	No	No

As nouns, brass instrument is a hypernym of fluegelhorn; that is, brass instrument is a word with a broader meaning than fluegelhorn:

fluegelhorn: a brass instrument resembling a cornet but with a wider bore
brass instrument: a wind instrument that consists of a brass tube (usually of variable length) that is blown by means of a cup-shaped or funnel-shaped mouthpiece

Other hypernyms of fluegelhorn include brass.

fluegelhorn (noun)	brass instrument (noun)
a brass instrument resembling a cornet but with a wider bore	a wind instrument that consists of a brass tube (usually of variable length) that is blown by means of a cup-shaped or funnel-shaped mouthpiece