A reredos or raredos is an altarpiece

Altarpiece

An altarpiece is a picture or relief representing a religious subject and suspended in a frame behind the altar of a church. The altarpiece is often made up of two or more separate panels created using a technique known as panel painting. It is then called a diptych, triptych or polyptych for two,...

, or a screen or decoration behind the altar

Altar

An altar is any structure upon which offerings such as sacrifices are made for religious purposes. Altars are usually found at shrines, and they can be located in temples, churches and other places of worship...

 in a church, usually depicting religious iconography

Iconography

Iconography is the branch of art history which studies the identification, description, and the interpretation of the content of images. The word iconography literally means "image writing", and comes from the Greek "image" and "to write". A secondary meaning is the painting of icons in the...

 or images. In French and sometimes in English, this is called a retable

Retable

A retable is a framed altarpiece, raised slightly above the back of the altar or communion table, on which are placed the cross, ceremonial candlesticks and other ornaments....

; in Spanish a retablo, etc. It can be made of stone, wood, metal, ivory

Ivory

Ivory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and...

, or a combination of materials. The images may be painted, carved, gilded

Gilding

The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...

, composed of mosaic

Mosaic

Mosaic is the art of creating images with an assemblage of small pieces of colored glass, stone, or other materials. It may be a technique of decorative art, an aspect of interior decoration, or of cultural and spiritual significance as in a cathedral...

s, and/or embedded with niche

Niche (architecture)

A niche in classical architecture is an exedra or an apse that has been reduced in size, retaining the half-dome heading usual for an apse. Nero's Domus Aurea was the first semi-private dwelling that possessed rooms that were given richly varied floor plans, shaped with niches and exedras;...

s for statue

Statue

A statue is a sculpture in the round representing a person or persons, an animal, an idea or an event, normally full-length, as opposed to a bust, and at least close to life-size, or larger...

s. Sometimes a tapestry

Tapestry

Tapestry is a form of textile art, traditionally woven on a vertical loom, however it can also be woven on a floor loom as well. It is composed of two sets of interlaced threads, those running parallel to the length and those parallel to the width ; the warp threads are set up under tension on a...

 is used, or other fabric such as silk

Silk

Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...

 or velvet

Velvet

Velvet is a type of woven tufted fabric in which the cut threads are evenly distributed,with a short dense pile, giving it a distinctive feel.The word 'velvety' is used as an adjective to mean -"smooth like velvet".-Composition:...

.

Reredos is derived

Etymology

Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...

 through Middle English from the 14th century Anglo-Norman areredos, which in turn is from arere behind +dos back, from Latin dorsum. The term referred generally to an open hearth of a fireplace or a screen placed behind a table. Used in the 14th and 15th centuries, reredos had become nearly obsolete

Obsolescence

Obsolescence is the state of being which occurs when an object, service or practice is no longer wanted even though it may still be in good working order. Obsolescence frequently occurs because a replacement has become available that is superior in one or more aspects. Obsolete refers to something...

until revived in the 19th century.

The retable may have become part of the reredos when an altar was moved away from the wall. For altars that are still against the wall, the retable often sits on top of the altar, at the back, particularly when there is no reredos (a dossal curtain or something similar is used instead). The retable is also where the altar cross, flowers and "office light" type candlesticks sit.