noun

1. Hell; the bottomless pit; primeval chaos; a confined subterranean ocean.

2. (frequently figurative) A bottomless or unfathomed depth, gulf, or chasm; hence, any deep, immeasurable; any void space.

3. Anything infinite, immeasurable, or profound.

4. Moral depravity; vast intellectual or moral depth.

5. An impending catastrophic happening.

6. The center of an escutcheon.

7. The abyssal zone.

8. A difference, especially a large difference, between groups.