piano accordion vs squeeze box

piano accordion and squeeze box both are nouns.

Word	Noun	Adjective	Verb	Adverb
piano accordion	Yes	No	No	No
squeeze box	Yes	No	No	No

As nouns, squeeze box is a hypernym of piano accordion; that is, squeeze box is a word with a broader meaning than piano accordion:

piano accordion: an accordion with a right-hand keyboard
squeeze box: a portable box-shaped free-reed instrument; the reeds are made to vibrate by air from the bellows controlled by the player

Other hypernyms of piano accordion include accordion.

piano accordion (noun)	squeeze box (noun)
an accordion with a right-hand keyboard	a portable box-shaped free-reed instrument; the reeds are made to vibrate by air from the bellows controlled by the player