Rules for the Punctuation of Appositives

Essential Appositives

• An essential appositive cannot be taken out without altering the meaning of the sentence. For example:

  Actress Susan Sarandon is known for the intelligence and versatility she brings to the screen.

  In this sentence, "Susan Sarandon" is an appositive for "actress." Her name is essential information -- without it the sentence would be too general to understand.

Nonessential Appositives

• A nonessential appositive can be taken out or changed without altering the meaning of the sentence. For example:

  Albert Einstein, the scientist with the funny hair, famously failed his college entrance exam.

  In this sentence, "the scientist with the funny hair" is not necessary for the meaning -- it simply adds additional information.

  One way to test for a nonessential appositive is simply to cover it up and reread the sentence:

  Albert Einstein famously failed his college entrance exam.

No Punctuation With an Essential Appositive

• You do not need any punctuation with an essential appositive. For example:

  My sister Amy is in the Marine Corps.

  The planet Mars looks red from a distance.

  The song "Stayin' Alive" was a disco hit in 1977.

Use Commas with a Nonessential Appositive

• Use commas around a nonessential appositive. For example:

  Queen Victoria, the daughter of Prince Edward, came to power at age 18.

  Without the commas, the reader might become confused as to who came to power at age 18. The commas clarify and set apart this information.

Appositives That Are Lists

• If the appositive is part of a list, use a colon. For example:

  I went to the store for four things: broccoli, cabbage, fish and milk.

  Note you do not need a colon in the following sentence:

  I went to the store for broccoli, cabbage, fish and milk.

  This is because there is no appositive to name or rename the groceries.

Appositives With Dashes

• Sometimes an appositive itself contains commas. When this is the case, use dashes to set off the entire appositive phrase so that the meaning is clear.

  Thomas Jefferson believed that certain human rights -- life, liberty, and the pursuit of happiness -- were inalienable.

  The appositive could also come at the end of the sentence. This would require only one dash:

  Thomas Jefferson believed that certain human rights were inalienable -- life, liberty, and the pursuit of happiness.