The Collaborative International Dictionary of English v.0.48:

Plenitude \Plen"i*tude\, n. [L. plenitudo, fr. plenus full; cf.
   F. plenitude.]
   1. The quality or state of being full or complete; fullness;
      completeness; abundance; as, the plenitude of space or
      power.
      [1913 Webster]

   2. Animal fullness; repletion; plethora. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

plenitude
    n 1: a full supply; "there was plenty of food for everyone"
         [syn: plenty, plentifulness, plenteousness,
         plenitude, plentitude]