We don't have synonyms for antidoron yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are anticodon, antigonon and antiporn.
(n) :
(Christianity, Eastern Orthodoxy, Eastern Catholicism) A piece of ordinary leavened bread, taken from remnants of loaves used for the Eucharist, which has been blessed but not consecrated; distributed in churches that use the Byzantine Rite.
(n) :
(Christianity, Eastern Orthodoxy, Eastern Catholicism) A piece of ordinary leavened bread, taken from remnants of loaves used for the Eucharist, which has been blessed but not consecrated; distributed in churches that use the Byzantine Rite.