black art vs thaumaturgy

black art and thaumaturgy both are nouns.

Word	Noun	Adjective	Verb	Adverb
black art	Yes	No	No	No
thaumaturgy	Yes	No	No	No

As nouns, thaumaturgy is a hypernym of black art; that is, thaumaturgy is a word with a broader meaning than black art:

black art: the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world
thaumaturgy: any art that invokes supernatural powers

Other hypernyms of black art include magic.

black art (noun)	thaumaturgy (noun)
the belief in magical spells that harness occult forces or evil spirits to produce unnatural effects in the world	an illusory feat; considered magical by naive observers
	any art that invokes supernatural powers