the.com/ocean floor

means The seabed — the solid ground beneath all that water, stretching from shallow coastal shelves down into trenches deep enough to swallow mountains.

from 'Ocean' traces back through Latin 'oceanus' to Greek 'ōkeanos,' the vast river the Greeks imagined circling the entire flat disk of the world — a boundary-sea, not a place to have a bottom at all. 'Floor' comes from Old English 'flor,' related to other Germanic words for a flat paved or leveled surface, the part of a room you stand on. Pairing them is almost a small joke: humans took a word for the ground under a roof and nailed it onto the one surface on Earth that's never had a ceiling we could see from below.