abyss

noun

• Hell; the bottomless pit; primeval chaos; a confined subterranean ocean.
• (frequently figurative) A bottomless or unfathomed depth, gulf, or chasm; hence, any deep, immeasurable; any void space.
• Anything infinite, immeasurable, or profound.
• Moral depravity; vast intellectual or moral depth.
• An impending catastrophic happening.
• The center of an escutcheon.
• The abyssal zone.
• A difference, especially a large difference, between groups.