agendum vs order of business

agendum and order of business both are nouns.

Word	Noun	Adjective	Verb	Adverb
agendum	Yes	No	No	No
order of business	Yes	No	No	No

As nouns, agendum and order of business are synonyms defined as:

agendum and order of business: a list of matters to be taken up (as at a meeting)

Other synonyms of agendum include agenda.

agendum (noun)	order of business (noun)
a list of matters to be taken up (as at a meeting)	a list of matters to be taken up (as at a meeting)