An abyss is an extremely deep or seemingly bottomless space. The word originally described the deepest parts of the ocean, where darkness is complete and the pressure would crush anything from the surface. Scientists exploring the ocean abyss have discovered bizarre creatures that glow in the dark and survive in conditions we once thought impossible for life.

The word also describes any deep, frightening gap or void. A mountain climber might peer nervously over the edge of a cliff into the abyss below. In stories, heroes sometimes must cross a narrow bridge over a yawning abyss, where one misstep means falling into the darkness.

Beyond physical spaces, abyss can describe anything that feels bottomless or overwhelming. Someone might say they're staring into an abyss of homework when they have so many assignments they can't see the end. A person facing a huge problem with no clear solution might feel like they're standing at the edge of an abyss.

The word carries a sense of both wonder and fear: the abyss is unknown, mysterious, and vast beyond imagining. When you use abyss, you're describing something so deep it makes you feel small and uncertain, confronted by a space that seems to have no end.