Abyss (noun)

A deep or seemingly bottomless chasm, cavity, or void, especially one in the earth's surface.

Origin:

Middle english abissus, from latin abyssus, from greek abyssos bottomless, from a- + byssos deep.

Examples:

1. He stared into the abyss of the Grand Canyon.
2. She was afraid of falling into the abyss.
3. The abyss of space was a topic of interest for him.
4. The abyss of the ocean is still not fully explored.
5. The abyss of poverty is difficult to escape.