The Collaborative International Dictionary of English v.0.48:

Agendum \A*gen"dum\ ([.a]*j[e^]n"d[u^]m), n.; pl. Agenda
   ([.a]*j[e^]n"d[.a]). [L., neut. of the gerundive of agere to
   act.]
   1. Something to be done; in the pl., a memorandum book; also,
      a list of items to be considered. See agenda.
      [1913 Webster]

   2. A church service; a ritual or liturgy. [In this sense,
      usually Agenda.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

agenda \agenda\ ([.a]*j[e^]n"d[.a]), n.
   a temporally organized plan for matters to be attended to.

   Syn: docket, schedule
        [WordNet 1.5 +PJC]

   2. A list of matters to be discussed (as at a meeting).

   Syn: agendum, docket, order of business
        [WordNet 1.5]

   3. A motive or set of goals; as, to have one's own agenda;
      especially, a secret motive; also called hidden agenda;
      as, some of the news commentators themselves have an
      agenda.

   Syn: goal, hidden motive, secret motive, hidden agenda.
        [PJC]

WordNet (r) 3.0 (2006):

agenda
    n 1: a temporally organized plan for matters to be attended to
         [syn: agenda, docket, schedule]
    2: a list of matters to be taken up (as at a meeting) [syn:
       agenda, agendum, order of business]