black humour vs black humor

black humour and black humor both are nouns.

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

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

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

black humour (noun)	black humor (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