black humor vs black humour

black humor and black humour both are nouns.

Word	Noun	Adjective	Verb	Adverb
black humor	Yes	No	No	No
black humour	Yes	No	No	No

As nouns, black humor and black humour are synonyms defined as:

black humor and black humour: the juxtaposition of morbid and farcical elements (in writing or drama) to give a disturbing effect

black humor (noun)	black humour (noun)
the juxtaposition of morbid and farcical elements (in writing or drama) to give a disturbing effect	the juxtaposition of morbid and farcical elements (in writing or drama) to give a disturbing effect