CSS & Frontend

z-index

/zed ˈɪndeks/

Definition

A CSS property that controls the stacking order of positioned elements — higher values appear on top.

Example in context

"The modal overlay needs z-index: 1000; the dropdown, z-index: 200 — otherwise the dropdown bleeds through."

Related terms

Practice this term

Master z-index in context by working through exercises in the CSS & Frontend module. You'll see the term used in real engineering scenarios with multiple-choice, fill-in-the-blank, and matching drills.