discolouration vs discoloration

discolouration and discoloration both are nouns.

Word	Noun	Adjective	Verb	Adverb
discolouration	Yes	No	No	No
discoloration	Yes	No	No	No

As nouns, discolouration and discoloration are synonyms defined as:

discolouration and discoloration: the act of changing the natural color of something by making it duller or dingier or unnatural or faded

As nouns, discolouration and discoloration are synonyms defined as:

Other synonyms of discolouration include stain.

discolouration (noun)	discoloration (noun)
the act of changing the natural color of something by making it duller or dingier or unnatural or faded	the act of changing the natural color of something by making it duller or dingier or unnatural or faded
a soiled or discolored appearance	a soiled or discolored appearance