Source : Webster's Revised Unabridged Dictionary (1913)

Erectile \E*rect"ile\, a. [Cf. F. ['e]rectile.]
   Capable of being erected; susceptible of being erected of
   dilated.

   {Erectile tissue} (Anat.), a tissue which is capable of being
      greatly dilated and made rigid by the distension of the
      numerous blood vessels which it contains.

Source : WordNet®

erectile tissue
     n : vascular tissue capable of filling with blood and becoming
         rigid