Grammar Quest—Commas & Appositives
An appositive identifies or renames a preceding noun or pronoun. An appositive can be a noun or a noun phrase. You must offset an appositive with commas.
Barak O’Bama, the first African American President of the United States, will address the nation.
Emma, our lovable and enthusiastic puppy, was a new edition to our home.
Macee, the smartest girl in the class, was always ruining the class grading curve.
Mary Shelly, the novelist, was a forerunner to other contemporary science fiction writers.
An exception to this rule—because there always are exceptions to grammar rules—is that you do not use commas with restrictive appositives. A restrictive appositive is essential to the meaning of the sentence.
Nine year old student Olivia Nelson almost won the 3rd grade spelling bee.
The novelist Mary Shelly was a forerunner to other contemporary science fiction writers.
If you off set “Olivia Nelson” with commas as with an appositive, the sentence does not make sense. “Olivia Nelson” is essential to the sentence. This means that it is a restrictive appositive and does not require commas.