ABYSS n.
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.
ABYSSAL a.
yssal zone (Phys. Geog.), one of the belts or zones into which Sir E. Forbes divides the bottom of the sea in describing its plants, animals, etc. It is the one furthest from the shore, embracing all beyond one hundred fathoms deep. Hence, abyssal animals, plants, etc.