agendum

[uh-jen-duh m] /əˈdʒɛn dəm/
noun, plural agenda
[uh-jen-duh] /əˈdʒɛn də/ (Show IPA), agendums.
1.
an agenda.
2.
something that is to be done.
3.
an item on an agenda.
Origin
1895-1900; < Latin, gerund of agere to do
Usage note
See agenda.

agenda

[uh-jen-duh] /əˈdʒɛn də/
noun, formally a plural of, agendum but usually used as a singular with plural, agendas or agenda.
1.
a list, plan, outline, or the like, of things to be done, matters to be acted or voted upon, etc.:
The chairman says we have a lengthy agenda this afternoon.
Origin
1745-55; < Latin, plural of agendum that which is to be done, gerund of agere to do; the plural orig. carried a collective sense denoting the various items to be transacted
Related forms
agendaless, adjective
Usage note
Agenda, “things to be done,” is the plural of the Latin gerund agendum and is used today in the sense “a plan or list of matters to be acted upon.” In that sense it is treated as a singular noun; its plural is usually agendas: The agenda is ready for distribution. The agendas of last year's meetings are printed in the official minutes. The singular agendum, meaning “an item on an agenda,” is rare.
British Dictionary definitions for agendum

agenda

/əˈdʒɛndə/
noun
1.
(functioning as sing) Also called agendum. a schedule or list of items to be attended to
2.
(functioning as pl) Also called agendas, agendums. matters to be attended to, as at a meeting of a committee
Word Origin
C17: Latin, literally: things to be done, from agere to do
Word Origin and History for agendum

agenda

n.

1650s, from Latin agenda, literally "things to be done," neuter plural of agendus, gerundive of agere "to do" (see act (n.)). Originally theological (opposed to matters of belief), sense of "items of business to be done at a meeting" first attested 1882. "If a singular is required (=one item of the agenda) it is now agendum, the former singular agend being obsolete" [Fowler].