The Collaborative International Dictionary of English v.0.48:

Palatial \Pa*la"tial\, a. [L. palatium palace. See Palace.]
   Of or pertaining to a palace; suitable for a palace;
   resembling a palace; royal; magnificent; as, palatial
   structures. "Palatial style." --A. Drummond.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Palatial \Pa*la"tial\, a. [From Palate.] (Anat.)
   Palatal; palatine. [Obs.] --Barrow.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Palatial \Pa*la"tial\, n.
   A palatal letter. [Obs.] --Sir W. Jones.
   [1913 Webster]

WordNet (r) 3.0 (2006):

palatial
    adj 1: relating to or being a palace; "the palatial residence"
    2: suitable for or like a palace; "palatial furnishings"; "a
       palatial yacht"

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "palatial":
   Babylonian, Corinthian, awe-inspiring, awful, barbaric, classy,
   deluxe, domal, domestic, domiciliary, elaborate, elegant,
   extravagant, fancy, fine, glorious, grand, grandiose, home,
   household, imposing, impressive, luscious, lush, luxuriant,
   luxurious, magnificent, majestic, manorial, mansional, monumental,
   noble, opulent, palatine, plush, posh, princely, proud, regal,
   residential, residentiary, rich, ritzy, splendacious, splendid,
   splendiferous, stately, sumptuous, superb, superfancy, superfine,
   swank, swanky, swell