What is "phyletism"

Phyletism or ethnophyletism (from Greek ἔθνος ethnos "nation" and φυλετισμός phyletismos "tribalism") is the principle of nationalities applied in the ecclesiastical domain: in other words, the conflation between Church and nation. The term ethnophyletismos designates the idea that a local autocephalous Church should be based not on a local [ecclesial] criterion, but on an ethnophyletist, national or linguistic one. It was used at the Holy and Great [Μείζων Meizon "enlarged"] pan-Orthodox Synod in Constantinople on 10 September 1872 to qualify "phyletist (religious) nationalism", which was condemned as a modern ecclesial heresy: the Church should not be confused with the destiny of a single nation or a single race.