The Collaborative International Dictionary of English v.0.48:

Level \Lev"el\, v. t. [imp. & p. p. Leveled (-[e^]ld) or
   Levelled; p. pr. & vb. n. Leveling or Levelling.]
   1. To make level; to make horizontal; to bring to the
      condition of a level line or surface; hence, to make flat
      or even; as, to level a road, a walk, or a garden.
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   2. To bring to a lower level; to overthrow; to topple down;
      to reduce to a flat surface; to lower.
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            And their proud structures level with the ground.
                                                  --Sandys.
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            He levels mountains and he raises plains. --Dryden.
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   3. To bring to a horizontal position, as a gun; hence, to
      point in taking aim; to aim; to direct.
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            Bertram de Gordon, standing on the castle wall,
            leveled a quarrel out of a crossbow.  --Stow.
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   4. Figuratively, to bring to a common level or plane, in
      respect of rank, condition, character, privilege, etc.;
      as, to level all the ranks and conditions of men.
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   5. To adjust or adapt to a certain level; as, to level
      remarks to the capacity of children.
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            For all his mind on honor fixed is,
            To which he levels all his purposes.  --Spenser.
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The Collaborative International Dictionary of English v.0.48:

Leveling \Lev"el*ing\, n. [Written also levelling.]
   1. The act or operation of making level.
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   2. (Surveying) The art or operation of using a leveling
      instrument for finding a horizontal line, for ascertaining
      the differences of level between different points of the
      earth's surface included in a survey, for establishing
      grades, etc., as in finding the descent of a river, or
      locating a line of railroad.
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   Leveling instrument. See Surveyor's level, under Level,
      n.

   Leveling staff, a graduated rod or staff used in connection
      with a leveling instrument for measuring differences of
      level between points.
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WordNet (r) 3.0 (2006):

leveling
    n 1: changing the ground level to a smooth horizontal or gently
         sloping surface [syn: grading, leveling]
    2: complete destruction of a building [syn: razing,
       leveling, tearing down, demolishing]
    3: the act of making equal or uniform [syn: equalization,
       equalisation, leveling]