The Collaborative International Dictionary of English v.0.48:

Sudarium \Su*da"ri*um\, n. [L., a handkerchief.] (Eccl.)
   The handkerchief upon which the Savior is said to have
   impressed his own portrait miraculously, when wiping his face
   with it, as he passed to the crucifixion.
   [1913 Webster]