Someone who has bathophobia has an abnormal fear of what?

The name of this specific phobia provides a direct clue to its meaning. It comes from the Greek words "bathos," meaning depth, and "phobos," meaning fear. Therefore, someone with this condition experiences an intense and irrational fear of deep places, whether they are filled with water or not. This anxiety can be triggered by looking into a deep swimming pool, peering over the edge of a canyon, or even staring down a long, dark hallway.

It is important to distinguish this from similar-sounding phobias. While it often involves water, it is not the same as aquaphobia, which is the fear of water itself. A person with bathophobia might be perfectly comfortable wading in a shallow part of the ocean. It also differs from thalassophobia, which is a more specific fear of large, dark, and deep bodies of open water and what unknown things might be lurking within them.

For someone with this condition, the trigger is the perception of a profound, and often overwhelming, vertical drop. The core of the fear is not necessarily what lies at the bottom, but the vast, empty, and unknown space in between. It is the sheer concept of the void itself that causes the distress.