agendum

Etymology
From, substantive use of the neuter singular of , future passive participle (gerundive) of.

Noun

 * 1)  A task which ought to be done.
 * 2)  Something to be done; a practical duty, rather than an article of faith.

Usage notes
Agendum is a word now so common in the plural that its plural form is now generally taken to be a collective singular form, with the special meaning of a list of tasks which are to be done. A similar case is datum and its plural data which is now commonly taken to be a collective singular and synonymous with 'information'.