The Collaborative International Dictionary of English v.0.48:

Biodynamics \Bi`o*dy*nam"ics\, n. [Gr. bi`os life + E.
   dynamics.]
   1. (Biol.) The doctrine of vital forces or energy. [archaic]
      [1913 Webster]

   2. The branch of biology which treats of the active vital
      phenomena of organisms; -- opposed to biostatics.
      [Webster 1913 Suppl.]