Source : Webster's Revised Unabridged Dictionary (1913)

Immaculate \Im*mac"u*late\, 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.

         Were but my soul as pure From other guilt as that,
         Heaven did not hold One more immaculate. --Denham.

         Thou sheer, immaculate and silver fountain. --Shak.

   {Immaculate conception} (R. C. Ch.), the doctrine that the
      Virgin Mary was conceived without original sin. --
      {Im*mac"u*late*ly}, adv. -- {Im*mac"u*late*ness}, n.

Source : WordNet®

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