Klavier vs harpsichord

Klavier and harpsichord both are nouns.

Word	Noun	Adjective	Verb	Adverb
Klavier	Yes	No	No	No
harpsichord	Yes	No	No	No

As nouns, harpsichord is a hyponym of Klavier; that is, harpsichord is a word with a more specific, narrower meaning than Klavier:

Klavier: a stringed instrument that has a keyboard
harpsichord: a clavier with strings that are plucked by plectra mounted on pivots

Other hyponyms of Klavier include cembalo.

Klavier (noun)	harpsichord (noun)
a stringed instrument that has a keyboard	a clavier with strings that are plucked by plectra mounted on pivots