antimension

noun, plural an·ti·men·si·a [ahn-dee-meen-see-ah; English ahn-dee-meen-see-uh] /ˌɑn diˈmin si ɑ; English ˌɑn diˈmin si ə/. Greek Orthodox Church.

1. a consecrated linen or silk cloth, kept on an altar, to which is sewn a linen or silk bag containing relics of saints.