The Collaborative International Dictionary of English v.0.48:

Gradatory \Grad"a*to*ry\, a. [See Grade.]
   1. Proceeding step by step, or by gradations; gradual.
      [1913 Webster]

            Could we have seen [Macbeth's] crimes darkening on
            their progress . . . could this gradatory apostasy
            have been shown us.                   --A. Seward.
      [1913 Webster]

   2. (Zool.) Suitable for walking; -- said of the limbs of an
      animal when adapted for walking on land.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gradatory \Grad"a*to*ry\, n. [Cf. LL. gradatarium.] (Arch.)
   A series of steps from a cloister into a church.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gradatory
    adj 1: taking place by degrees [syn: gradational, gradatory,
           graduated]