shepherd's pipe vs fipple flute

shepherd's pipe and fipple flute both are nouns.

Word	Noun	Adjective	Verb	Adverb
shepherd's pipe	Yes	No	No	No
fipple flute	Yes	No	No	No

As nouns, fipple flute is a hypernym of shepherd's pipe; that is, fipple flute is a word with a broader meaning than shepherd's pipe:

shepherd's pipe: a small fipple flute with four finger holes and two thumb holes
fipple flute: a tubular wind instrument with 8 finger holes and a fipple mouthpiece

Other hypernyms of shepherd's pipe include fipple pipe, recorder, vertical flute.

shepherd's pipe (noun)	fipple 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 small bagpipe formerly popular in France