The Collaborative International Dictionary of English v.0.48:

Gratulatory \Grat"u*la*to*ry\, a. [L. gratulatorius.]
   Expressing gratulation or joy; congratulatory.
   [1913 Webster]

         The usual groundwork of such gratulatory odes. --Bp.
                                                  Horsley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gratulatory
    adj 1: expressive of sympathetic pleasure or joy on account of
           someone's success or good fortune; "a congratulatory
           telegram"; "the usual congratulatory crowd was
           conspicuously absent"; "a gratulatory address" [syn:
           congratulatory, gratulatory]