Source : Webster's Revised Unabridged Dictionary (1913)

Agendum \A*gen"dum\, n.; pl. {Agenda}. [L., neut. of the
   gerundive of agere to act.]
   1. Something to be done; in the pl., a memorandum book.

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

Source : WordNet®

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