spiracle vs stigma

spiracle and stigma both are nouns.

Word	Noun	Adjective	Verb	Adverb
spiracle	Yes	No	No	No
stigma	Yes	No	No	No

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

Other hyponyms of spiracle include blowhole.

spiracle (noun)	stigma (noun)
a breathing orifice	a skin lesion that is a diagnostic sign of some disease
	an external tracheal aperture in a terrestrial arthropod
	a symbol of disgrace or infamy
	the apical end of the style where deposited pollen enters the pistil