The Collaborative International Dictionary of English v.0.48:

Soil \Soil\, n. [OE. soile, F. sol, fr. L. solum bottom, soil;
   but the word has probably been influenced in form by soil a
   miry place. Cf. Saloon, Soil a miry place, Sole of the
   foot.]
   1. The upper stratum of the earth; the mold, or that compound
      substance which furnishes nutriment to plants, or which is
      particularly adapted to support and nourish them.
      [1913 Webster]

   2. Land; country.
      [1913 Webster]

            Must I thus leave thee, Paradise? thus leave
            Thee, native soil?                    --Milton.
      [1913 Webster]

   3. Dung; faeces; compost; manure; as, night soil.
      [1913 Webster]

            Improve land by dung and other sort of soils.
                                                  --Mortimer.
      [1913 Webster]

   Soil pipe, a pipe or drain for carrying off night soil.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Soil pipe \Soil pipe\
   A pipe or drain for carrying off night soil.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

soil pipe
    n 1: drain that conveys liquid waste from toilets, etc.