A cornice is a decorative strip that runs along the top of a wall, often where the wall meets the ceiling. If you look up in older buildings, libraries, or grand houses, you might notice an ornamental band with carved patterns, molded designs, or elegant curves running horizontally around the room. That's a cornice.

Cornices were especially popular in classical Greek and Roman architecture, and they're still used today to make rooms feel more finished and elegant. The design might be simple and clean, or it might feature elaborate carvings of leaves, flowers, or geometric patterns. Architects use cornices to create a visual boundary, helping your eye understand where one part of a building ends and another begins.

In mountaineering, the word has a completely different meaning: a cornice is an overhanging edge of snow that forms on a mountain ridge, shaped by wind into a wave-like curve. These cornices can be beautiful but dangerous, since they sometimes collapse under a climber's weight. Experienced mountaineers learn to recognize cornices and avoid walking on them, staying safely back from the edge where solid ground lies beneath the snow.