glottis vs vocal organ

glottis and vocal organ both are nouns.

Word	Noun	Adjective	Verb	Adverb
glottis	Yes	No	No	No
vocal organ	Yes	No	No	No

As nouns, vocal organ is a hypernym of glottis; that is, vocal organ is a word with a broader meaning than glottis:

glottis: the vocal apparatus of the larynx; the true vocal folds and the space between them where the voice tone is generated
vocal organ: any of the organs involved in speech production

Other hypernyms of glottis include organ of speech, speech organ.

glottis (noun)	vocal organ (noun)
the vocal apparatus of the larynx; the true vocal folds and the space between them where the voice tone is generated	any of the organs involved in speech production