The Collaborative International Dictionary of English v.0.48:

Dirt \Dirt\ (d[~e]rt), n. [OE. drit; kin to Icel. drit
   excrement, dr[imac]ta to dung, OD. drijten to dung, AS.
   gedr[imac]tan.]
   1. Any foul of filthy substance, as excrement, mud, dust,
      etc.; whatever, adhering to anything, renders it foul or
      unclean; earth; as, a wagonload of dirt.
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            Whose waters cast up mire and dirt.   --Is. lvii.
                                                  20.
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   2. Meanness; sordidness.
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            Honors . . . thrown away upon dirt and infamy.
                                                  --Melmoth.
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   3. In placer mining, earth, gravel, etc., before washing.
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   Dirt bed (Geom.), a layer of clayey earth forming a stratum
      in a geological formation. Dirt beds are common among the
      coal measures.

   Dirt eating.
      (a) The use of certain kinds of clay for food, existing
          among some tribes of Indians; geophagism. --Humboldt.
      (b) (Med.) Same as Chthonophagia.

   Dirt pie, clay or mud molded by children in imitation of
      pastry. --Otway (1684).

   To eat dirt, to submit in a meanly humble manner to
      insults; to eat humble pie.
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