This is one of those terms that could make your eyes cross, but when you come right down to it, it pretty much defines itself. Think of “nonrestrictive” as “non-essential”, which is not actually the technical definition. It’s giving extra or parenthetical information.
Here’s the technical definition: Restrictive clauses limit the possible meaning of a preceding subject. Nonrestrictive clauses tell you something about a preceding subject, but they do not limit, or restrict, the meaning of that subject.
Okay, let’s see an example to make it more user-friendly.
The suspect in the lineup, who owns a red car, committed the crime. The sentence makes sense without the phrase “who owns a red car” and doesn’t actually “need” that qualifier. It’s not essential to the crime in this case to know he owns a red car.
However, The suspect in the lineup who has red hair committed the crime is a “restrictive clause, because it IS essential to the meaning of the sentence. We know it’s not the suspect with the brown hair who is the criminal, but the one with red hair.
Another example: Tony Morrison’s fifth novel, Beloved, won the Pulitzer Prize in 1988. (This is a non-restrictive phrase. The word “fifth” identifies the novel, but we don’t necessarily need the title to make sense of the sentence.)
But: Tony Morrison’s novel The Bluest Eye is about an African American girl who longs for blue eyes. (This is a restrictive phrase, because Morrison has written more than one novel, so the title is essential to identify which book it is.)
As you can see from the examples, non-restrictive elements are set aside by commas (like parenthetical phrases), where restrictive phrases are not. That can be quite confusing (and I would normally put commas around The Bluest Eye), so we really have to look carefully at the meaning of the sentence with or without the phrase to determine which one it is.
A native Montanan, Heidi M. Thomas now lives in Northwest Washington. Her first novel, Cowgirl Dreams, is based on her grandmother, and the sequel, Follow the Dream, has recently won the national WILLA Award. Heidi has a degree in journalism, a certificate in fiction writing, and is a member of Northwest Independent Editors Guild. She teaches writing and edits, blogs, and is working on the next books in her “Dare to Dream” series.