I think it’s that the Greek “hagios” (holy) and the Latin “Sanctus” can both be translated “Saint” in English. Aside from the fact that the East doesn’t have a formal process for canonizing people officially as Saints, the ancient tradition is simply to refer to “holy ones” as “saint” in English. When we sing the Litany of the Saints, we sing, “Holy Michael” (archangel), “Holy Abraham,” “Holy Catherine of Siena” and so forth.
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