The Collaborative International Dictionary of English v.0.48:

Tetanus \Tet"a*nus\, n. [L., fr. Gr. ?, fr. ? stretched, ? to
   stretch.]
   1. (Med.) A painful and usually fatal disease, resulting
      generally from a wound, and having as its principal
      symptom persistent spasm of the voluntary muscles. When
      the muscles of the lower jaw are affected, it is called
      locked-jaw, or lickjaw, and it takes various names
      from the various incurvations of the body resulting from
      the spasm.
      [1913 Webster]

   2. (Physiol.) That condition of a muscle in which it is in a
      state of continued vibratory contraction, as when
      stimulated by a series of induction shocks.
      [1913 Webster]