The Collaborative International Dictionary of English v.0.48:

Sindon \Sin"don\, n. [L., a kind of fine Indian cotton stuff,
   Gr. ???.]
   1. A wrapper. [Obs.] "Wrapped in sindons of linen." --Bacon.
      [1913 Webster]

   2. (Surg.) A small rag or pledget introduced into the hole in
      the cranium made by a trephine. --Dunglison.
      [1913 Webster]