Appositives are grammatical elements, normally noun phrases, which are placed side by side, with one element serving to identify the other. The two units are grammatically parallel and refer to the same noun, creating smoother language and conveying multiple pieces of information in one sentence.

"Carole Baskin is the director of Big Cat Rescue" + "Carole Baskin has a missing husband" = "Carole Baskin, director of Big Cat Rescue, has a missing husband."

Restrictive Versus Nonrestrictive

A restrictive appositive provides information essential to identifying the element in apposition. It limits or clarifies that phrase in some crucial way, and the meaning of the sentence would change if the appositive were removed. Restrictive appositives are not set off by commas. The sentences below use restrictive appositives.

He likes the television show "Tiger King."

• There are a lot of television shows, but he likes a particular one.

Presidential candidate Joe Schreibvogel hosted an event downtown.

• Try reading the sentence without the clause in question. If the sentence is awkward or unintelligible without the clause, no commas are needed.

Tip: Small articles can make the difference in whether the sentence makes grammatical sense or not:

• He enlisted the help of a local lawyer, Rob McDuff.
• He enlisted the help of local lawyer Rob McDuff.

A nonrestrictive appositive provides information that is not critical to identifying the phrase in apposition. It provides nonessential information, and the essential meaning of the sentence would not change if the appositive were removed. Nonrestrictive appositives are set off by commas. The sentences below use nonrestrictive appositives.

Her pet tiger, Rajah, was Jasmine's best friend.
Rajah, her pet tiger, was Jasmine's best friend.

The same phrase can be a restrictive appositive in one context and a nonrestrictive appositive in another:
- My brother Nathan is here. - Restrictive: I have many brothers, and the one named Nathan is here.
- My brother, Nathan, is here. - Non-restrictive: I have only one brother and, as an aside, his name is Nathan.

• If there is any doubt that the appositive is non-restrictive, do not use commas.