Source : Webster's Revised Unabridged Dictionary (1913)

Pronate \Pro"nate\, a. [L. pronatus, p. p. of pronare to bend
   forward. See Prone.]
   Somewhat prone; inclined; as, pronate trees. --Kane.

Source : WordNet®

pronate
     v : turn the forearm or the hand so that the palm is directed
         downwards