[1] : The Collaborative International Dictionary of English v.0.48

immaculate \immac"ulate\, a. l. immaculatus; pref. im- not +
   maculatus, p. p. of maculare to spot, stane, fr. macula spot.
   see mail armor.
   without stain or blemish; spotless; undefiled; clear; pure.
   1913 webster

         were but my soul as pure
         from other guilt as that, heaven did not hold
         one more immaculate.                     --denham.
   1913 webster

         thou sheer, immaculate and silver fountain. --shak.
   1913 webster

   immaculate conception r. c. ch., the doctrine that the
      virgin mary was conceived without original sin. --
      immac"ulately, adv. -- immac"ulateness, n.
      1913 webster
see also:
mail immaculate conception immac"ulately immac"ulateness 

[2] : WordNet (r) 2.0

immaculate conception
     n 1: roman catholic holy day first celebrated in 1854 syn: december
          8
     2: christianity the roman catholic doctrine that the virgin
        mary was conceived without any stain of original sin
see also:
december 8 

[3] : Moby Thesaurus II by Grady Ward, 1.0

34 moby thesaurus words for "immaculate conception":
   dei mater, deipara, holy mary, mariolatry, mariology,
   mother of god, notre dame, our lady, queen of angels,
   queen of heaven, regina angelorum, regina coeli,
   sancta virgo virginum, stella maris, theotokos,
   virgin most glorious, virgin most merciful, virgin most powerful,
   virgin most renowned, virgin most venerable, virgin most wise,
   virgo clemens, virgo gloriosa, virgo potens, virgo praedicanda,
   virgo sapientissima, virgo sponsa dei, virgo veneranda,
   mater dolorosa, the blessed virgin, the sorrowful mother,
   the virgin, the virgin mary, the virgin mother

Conception >> C Words
Conception, definition of term: Conception
conception_pag1.html

Immaculate >> I Words
Immaculate, definition of term: Immaculate
immaculate_pag1.html

Immaculate Conc >> I Words
Immaculate Conc, definition of term: Immaculate Conc
immaculate+conc_pag1.html