solfa syllable vs si

solfa syllable and si both are nouns.

Word	Noun	Adjective	Verb	Adverb
solfa syllable	Yes	No	No	No
si	Yes	No	No	No

As nouns, si is a hyponym of solfa syllable; that is, si is a word with a more specific, narrower meaning than solfa syllable:

solfa syllable: one of the names for notes of a musical scale in solmization
si: the syllable naming the seventh (subtonic) note of any musical scale in solmization

Other hyponyms of solfa syllable include do, doh, ut, ray, re, mi, fa, so, soh, sol, la, lah, te, ti.

solfa syllable (noun)	si (noun)
one of the names for notes of a musical scale in solmization	the syllable naming the seventh (subtonic) note of any musical scale in solmization