Emily Dickinson Lexicon

A-BYSS', n. [Gr. αβυσσος, bottomless, from α privative and, βυσσος, bottom, Ion. for βυθος, See Bottom.]

1. A bottomless gulf; used also for a deep mass of waters, supposed to have encompassed the earth before the flood. Darkness was upon the face of the deep, [or abyss, as it is in the Septuagint.] Gen. i. 2. The word is also used for an immense cavern or cave in the earth in which God is supposed to have collected all the waters or the third day of the creation. It is used also for hell, Erebus. That which is immeasurable; that in which any thing is lost. Thy throne is darkness, in the abyss of light. – Milton. The abyss of time. – Dryden.
2. In antiquity, the temple of Proserpine, so called from its immense treasures it was supposed to contain.
3. In heraldry, the center of an escutcheon. He bears azure, a fleur de lis, in abyss.