The Collaborative International Dictionary of English v.0.48:

Detritus \De*tri"tus\, n. [F. d['e]tritus, fr. L. detritus, p.
   p. of deterere. See Detriment.]
   1. (Geol.) A mass of substances worn off from solid bodies by
      attrition, and reduced to small portions; as, diluvial
      detritus.
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   Note: For large portions, the word d['e]bris is used.
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   2. Hence: Any fragments separated from the body to which they
      belonged; any product of disintegration.
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            The mass of detritus of which modern languages are
            composed.                             --Farrar.
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WordNet (r) 3.0 (2006):

detritus
    n 1: the remains of something that has been destroyed or broken
         up [syn: debris, dust, junk, rubble, detritus]
    2: loose material (stone fragments and silt etc) that is worn
       away from rocks