Source : Webster's Revised Unabridged Dictionary (1913)

Ectoparasite \Ec`to*par"a*site\, n. (Zo["o]l.)
   Any parasite which lives on the exterior of animals; --
   opposed to {endoparasite}. -- {Ec`to*par`a*sit"ic}, a.

Source : WordNet®

ectoparasite
     n : any external parasitic organism (as fleas) [syn: {ectozoan},
          {ectozoon}, {epizoan}, {epizoon}]