rere·dos 
(rîrdŏs′, rîrĭ-, rĕrĭ-)
(rîrdŏs′, rîrĭ-, rĕrĭ-)n.
1. A decorative screen or facing on the wall at the back of an altar.
2. The back of an open hearth of a fireplace.
[Middle English, from Anglo-Norman, from areredos : arere, behind (Latin ad-, ad- + Latin retrō, backward; see re- in the Appendix of Indo-European roots) + dos, back (from Latin dorsum).]