The Collaborative International Dictionary of English v.0.48:

Avidity \A*vid"i*ty\, n. [L. aviditas, fr. avidus: cf. F.
   avidit['e]. See Avid.]
   Greediness; strong appetite; eagerness; intenseness of
   desire; as, to eat with avidity.
   [1913 Webster]

         His books were received and read with avidity.
                                                  --Milward.
   [1913 Webster]

WordNet (r) 3.0 (2006):

avidity
    n 1: a positive feeling of wanting to push ahead with something
         [syn: eagerness, avidity, avidness, keenness]