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The UK left the EU yesterday. It voted to leave in 2016. The UK made a new 50-pence coin for the occasion. It has the words: "Peace, prosperity and friendship with all nations" on it. A writer is unhappy. He thinks the punctuation is wrong. He said there should be an Oxford comma after the word "prosperity".
The Oxford comma is called the serial comma in the USA. It is used before the final "and" or "or" in a list of three or more items. People say an Oxford comma is unnecessary on the new coin because the meaning is very clear. A woman who studies words said the Oxford comma can help to better understand the writer's meaning.
Back to the Oxford comma lesson.