Although agenda is the plural of agendum in Latin, in standard modern English it is a normal singular noun with a normal plural form (agendas).
Agenda was previously the plural form of the original singular form "agendum".
The possessive form of the singular noun week is week's.example: The week's agenda is included in your welcome package.
Yes, agenda is an abstract noun, unless the agenda is in written form, then the document called the agenda is a concrete noun.
"Agendum" is the singular form of the word. The plural form is "agenda."
The singular form is agendum. The plural forms are agenda or agendums.
The word agendum has become almost extinct. Originally agenda was the plural of agendum, meaning 'a thing to be done'. However, it became applied to a list of things to be done, and in this, the most usual modern sense, agenda has become firmly singular (replacing agendum), with the plural agendas. Compare with data.
The noun family is the singular form; the plural form is families.
The noun children is the plural form of the singular noun child.
The noun 'fun' is a singular non-count noun, it has no plural form.
The singular form for the noun people is person.
The noun coach is the singular form. The plural form is coaches.
The form thief is the singular noun; the plural form is thieves.