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or

An appositional word or phrase introduced by or is set off by commas:
            He brandished his khanjar, or dagger, as he spoke.
 
When or introduces the final member of a series of three or more, it is preceded by a comma:
            coffee, tea, or milk
 
After a compound subject or a series connected with or, the verb agrees with the final member:
            wine or cocktails are served
            soft drinks, cocktails, or wine is served