pluralize vs pluralise

pluralize and pluralise both are verbs.

Word	Noun	Adjective	Verb	Adverb
pluralize	No	No	Yes	No
pluralise	No	No	Yes	No

As verbs, pluralize and pluralise are synonyms defined as:

pluralize and pluralise: mark with a grammatical morpheme that indicates plural

pluralize (verb)	pluralise (verb)
mark with a grammatical morpheme that indicates plural	mark with a grammatical morpheme that indicates plural