The Collaborative International Dictionary of English v.0.48:

Panegyric \Pan`e*gyr"ic\, Panegyrical \Pan`e*gyr"ic*al\, a. [L.
   panegyricus, Gr. panhgyrico`s, from panh`gyris an assembly of
   the people, a high festival; pa^, pa^n all + 'a`gyris,
   'agora`, an assembly.]
   Containing praise or eulogy; encomiastic; laudatory.
   "Panegyric strains." --Pope. -- Pan`e*gyr"ic*al*ly, adv.
   [1913 Webster]

         Some of his odes are panegyrical.        --Dryden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

panegyrical
    adj 1: formally expressing praise [syn: encomiastic,
           eulogistic, panegyric, panegyrical]