flageolet vs vertical flute

flageolet and vertical flute both are nouns.

Word	Noun	Adjective	Verb	Adverb
flageolet	Yes	No	No	No
vertical flute	Yes	No	No	No

As nouns, vertical flute is a hypernym of flageolet; that is, vertical flute is a word with a broader meaning than flageolet:

flageolet: a small fipple flute with four finger holes and two thumb holes
vertical flute: a tubular wind instrument with 8 finger holes and a fipple mouthpiece

Other hypernyms of flageolet include fipple flute, fipple pipe, recorder.

flageolet (noun)	vertical flute (noun)
a small fipple flute with four finger holes and two thumb holes	a tubular wind instrument with 8 finger holes and a fipple mouthpiece
a French bean variety with light-colored seeds; usually dried