alphabetiser vs alphabetizer

alphabetiser and alphabetizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
alphabetiser	Yes	No	No	No
alphabetizer	Yes	No	No	No

As nouns, alphabetiser and alphabetizer are synonyms defined as:

alphabetiser and alphabetizer: a literate person who can arrange items in alphabetical order

alphabetiser (noun)	alphabetizer (noun)
a literate person who can arrange items in alphabetical order	a literate person who can arrange items in alphabetical order