Source : Webster's Revised Unabridged Dictionary (1913)

Abyss \A*byss"\, n. [L. abyssus a bottomless gulf, fr. Gr. ?
   bottomless; 'a priv. + ? depth, bottom.]
   1. A bottomless or unfathomed depth, gulf, or chasm; hence,
      any deep, immeasurable, and, specifically, hell, or the
      bottomless pit.

            Ye powers and spirits of this nethermost abyss.
                                                  --Milton.

            The throne is darkness, in the abyss of light.
                                                  --Dryden.

   2. Infinite time; a vast intellectual or moral depth.

            The abysses of metaphysical theology. --Macaulay.

            In unfathomable abysses of disgrace.  --Burke.

   3. (Her.) The center of an escutcheon.

   Note: This word, in its leading uses, is associated with the
         cosmological notions of the Hebrews, having reference
         to a supposed illimitable mass of waters from which our
         earth sprung, and beneath whose profound depths the
         wicked were punished. --Encyc. Brit.

Source : WordNet®

abyss
     n : a bottomless gulf or pit; any unfathomable (or apparently
         unfathomable) cavity or chasm or void extending below
         (often used figuratively) [syn: {abysm}]