Plain English Meaning
The last part of a landing where you fly in over open water before reaching the runway. Because water gives your eyes nothing to judge height against, you can feel higher than you really are and end up flying too low.
Full Definition
A final approach to landing flown over a large body of water, where the lack of visual references between the aircraft and the runway can distort the pilot's perception of height and distance, often producing the illusion of being higher than actual altitude.
Context Anchor
Seen in discussions of optical illusions during landing, especially when approaching a runway near a lake, bay, ocean, or other large body of water.
Why Pilots Care
Pilots may descend too low without realizing it, increasing the of into water.