Q. What is the Oxford comma?
A. The Oxford (or serial) comma is a comma before “and” in a list of things
Q. Should I use the Oxford comma?
A. Technically the Oxford comma is neither right nor wrong, but some say it clutters the copy. Although, it does have its uses for clarity:
Q. When do I put a comma before “and” in a sentence?
A. When connecting two independent clauses
Q. Oh crud. I forgot what independent clauses are. How can I tell if I have two?
A. Independent clauses are parts of a sentence that can stand alone. A good rule of thumb I use is if you introduce a second subject in the second half of the sentence, you use a comma before “and.”
Fun fact! The Oxford comma was first introduced as rule in the 1905 edition of the Oxford University Press Style Guide, which is how it got the nickname. It is sometimes also called the Harvard comma since the Harvard press adheres to it as well.