The blank?

________ is a method of carving, or an object such as an engraved gem, item of jewellery or vessel made in this manner. It nearly always features a raised (positive) relief image; contrast with intaglio, which has a negative image. Originally, and still in discussing historical work, _________ only referred to works where the relief image was of a contrasting colour to the background; this was achieved by carefully carving a piece of material with a flat plane where two contrasting colours met, removing all the first colour except for the image to leave a contrasting background.

However, today the word is used more frequently in a different way altogether.