The Collaborative International Dictionary of English v.0.48:

Shock \Shock\, n. [Cf. Shag.]
   1. (Zool.) A dog with long hair or shag; -- called also
      shockdog.
      [1913 Webster]

   2. A thick mass of bushy hair; as, a head covered with a
      shock of sandy hair.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shockdog \Shock"dog`\, n. (Zool.)
   See 7th Shock, 1.
   [1913 Webster]