We don't have synonyms for reredosse yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are reredos, reremouse and reredoses.
(n) :
Archaic form of reredos. [(chiefly Western Christianity) A screen or decoration behind the altar in a church, usually depicting religious iconography or images, akin to the iconostasis of the Eastern Churches.]
(n) :
Archaic form of reredos. [(chiefly Western Christianity) A screen or decoration behind the altar in a church, usually depicting religious iconography or images, akin to the iconostasis of the Eastern Churches.]