An icon (from Greek εἰκών eikōn "image") is typically a painting depicting Christ, Mary, saints and/or angels, which is venerated among Eastern Orthodox, Oriental Orthodox, and in certain Catholic Churches.

Icons may also be cast in metal, carved in stone, embroidered on cloth, painted on wood, done in mosaic or fresco work, printed on paper or metal, etc. Icons are often illuminated with a candle or jar of oil with a wick. (Beeswax for candles and olive oil for oil lamps are preferred because they burn very cleanly, although other materials are sometimes used.) The illumination of religious images with lamps or candles is an ancient practice pre-dating Christianity.