The Collaborative International Dictionary of English v.0.48:

Grade \Grade\, v. t. [imp. & p. p. Graded; p. pr. & vb. n.
   Grading.]
   1. To arrange in order, steps, or degrees, according to size,
      quality, rank, etc.
      [1913 Webster]

   2. To reduce to a level, or to an evenly progressive ascent,
      as the line of a canal or road.
      [1913 Webster]

   3. (Stock Breeding) To cross with some better breed; to
      improve the blood of.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

graded \graded\ adj.
   1. ordered by some quantitative ranking; as, Reading tests of
      graded difficulty.

   Syn: ordered, ranked.
        [WordNet 1.5]

   2. leveled and drained but not paved; -- of roads.

   Syn: graveled.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

graded
    adj 1: arranged in a sequence of grades or ranks; "stratified
           areas of the distribution" [syn: graded, ranked,
           stratified]