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.
• (with article) An impending catastrophic happening.
• (heraldry) The center of an escutcheon.
• (oceanography) The abyssal zone.
• (figurative) A difference, especially a large difference, between groups.