This final comma at the end of a list placed directly before the main conjunction such as “and”, “or” or “nor” is called the serial comma or Oxford comma and it has long driven grammar nerds crazy.
Educators Alex Gendler and Jessica Ruby explain why the Oxford comma is so confounding and why inconsistency around this bit of punctuation still exists in “Grammar’s Great Divide: The Oxford Comma“, a Ted-Ed Lesson animated by ZedeM Media.
If you read “Bob, a DJ and a clown” on a guest list, are three people coming to the party, or only one? That depends on whether you’re for or against the Oxford comma — perhaps the most hotly contested punctuation mark of all time. When do we use one? Can it really be optional, or is there a universal rule?.