Elevation
A surface’s implied height above the page, communicated by its shadow — the higher the surface, the larger, softer, and farther the shadow falls.
Example usage
“Give the dropdown more elevation than the card it opens from — right now they read as the same layer.”
Editor’s note
Elevation turns shadow into hierarchy along the z-axis: what floats above what, which layer owns the moment. Material Design’s real contribution was rationing it — fixed levels instead of a free shadow slider, one imagined light source for the whole interface. Two things break the illusion: decorative shadows under things that sit above nothing, and dark mode, where shadow has nothing darker to fall on and height must be restated as a lighter surface.