professional organization vs professional organisation

professional organization and professional organisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
professional organization	Yes	No	No	No
professional organisation	Yes	No	No	No

As nouns, professional organization and professional organisation are synonyms defined as:

professional organization and professional organisation: an organization of and for professional people

professional organization (noun)	professional organisation (noun)
an organization of and for professional people	an organization of and for professional people