organ stop vs dulciana

organ stop and dulciana both are nouns.

Word	Noun	Adjective	Verb	Adverb
organ stop	Yes	No	No	No
dulciana	Yes	No	No	No

As nouns, dulciana is a hyponym of organ stop; that is, dulciana is a word with a more specific, narrower meaning than organ stop:

Other hyponyms of organ stop include diapason, diapason stop, flue stop, reed stop, sourdine, voix celeste, vox angelica.

organ stop (noun)	dulciana (noun)
a graduated set of organ pipes of like tone quality	the organ stop having a tone of soft sweet string quality