nebula vs speckle

nebula and speckle both are nouns.

Word	Noun	Adjective	Verb	Adverb
nebula	Yes	No	No	No
speckle	Yes	No	Yes	No

As nouns, speckle is a hypernym of nebula; that is, speckle is a word with a broader meaning than nebula:

Other hypernyms of nebula include dapple, fleck, maculation, patch, spot.

nebula (noun)	speckle (noun)
(pathology) a faint cloudy spot on the cornea	a small contrasting part of something
an immense cloud of gas (mainly hydrogen) and dust in interstellar space
cloudiness of the urine
a medicinal liquid preparation intended for use in an atomizer

nebula (verb)	speckle (verb)
	mark with small spots
	produce a mottled effect