The Collaborative International Dictionary of English v.0.48:

Celestial \Ce*les"tial\, a. [OF. celestial, celestied, fr. L.
   caelestic, fr. caelum heaved. See Cell.]
   1. Belonging to the a["e]rial regions, or visible heavens.
      "The twelve celestial signs." --Shak.
      [1913 Webster]

   2. Of or pertaining to the spiritual heaven; heavenly;
      divine. "Celestial spirits." "Celestial light," --Milton.
      [1913 Webster]

   3. Of, pertaining to, or characteristic of, the Chinese, or
      Celestial, Empire, of the Chinese people.
      [Webster 1913 Suppl.]

   Celestial city, heaven; the heavenly Jerusalem. --Bunyan.

   Celestial empire, China; -- so called from the Chinese
      words, tien chan, Heavenly Dynasty, as being the kingdom
      ruled over by the dynasty appointed by heaven. --S. W.
      Williams.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Celestial City
    n 1: phrases used to refer to Heaven; "the Celestial City was
         Christian's goal in Bunyan's `Pilgrim's Progress'" [syn:
         Celestial City, City of God, Heavenly City, Holy
         City]