Parallax -

: Elements shift slightly based on the movement of the user's cursor rather than scrolling.

: Background images move slower than foreground content, creating a layered, 3D feel as the user scrolls down the page.

: Content fades away or appears as users scroll past, often used to transition between story beats. 2. Optics & Shooting (Rifle Scopes)

What is a parallax effect? The definitive guide · Sketch Blog

In web design, parallax is a popular technique used to create immersion and 3D depth.

In precision shooting, "parallax" is a correction feature used to ensure accuracy.

: Specific layers tilt or scale (zoom in/out) as the user interacts with the page.