Source : WordNet®

sheep-tick
     n 1: wingless fly that is an external parasite on sheep and
          cattle [syn: {sheep ked}, {sheep tick}, {Melophagus
          Ovinus}]
     2: parasitic on sheep and cattle as well as humans; can
        transmit looping ill in sheep (acute viral disease of the
        nervous system); a vector for Lyme disease spirochete
        [syn: {sheep tick}, {Ixodes ricinus}]