Parallax
The depth cue in which nearer things move faster across the view than farther ones — in interfaces, layers scrolling at different rates to imply space behind the screen.
Example usage
“The hero runs three parallax layers, and the foreground type moves just a few percent faster than the photograph.”
Editor’s note
Parallax is the one depth cue you can feel through a scroll wheel, which is why marketing pages can’t leave it alone. At whisper volume — a background drifting slightly slower than the content — it reads as physical space. Bound tightly to scroll and turned up, it becomes scrolljacking, the genre where the page fights your thumb. True to this site’s own rule, this entry does not demonstrate it.