The Collaborative International Dictionary of English v.0.48:

Sordes \Sor"des\, n. [L., fr. sordere to be dirty or foul.]
   Foul matter; excretion; dregs; filthy, useless, or rejected
   matter of any kind; specifically (Med.), the foul matter that
   collects on the teeth and tongue in low fevers and other
   conditions attended with great vital depression.
   [1913 Webster]