Greek words borrowed through the literary tradition (not butter and bishop) are often recognizable from their spelling. Already in Latin, there were specific conventions for borrowing Greek. So Greek υ was written as 'y', αι as 'æ', οι as 'œ', φ as 'ph', etc. These conventions (which originally r ...

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English words of Greek origin, English words of Greek origin - The written form of Greek words in English, English words of Greek origin - Plurals, English words of Greek origin - Wiktionary

Read more here: » English words of Greek origin: Encyclopedia II - English words of Greek origin - The written form of Greek words in English