The Difference Between Essential and Nonessential Clauses

Also known as restrictive and nonrestrictive clauses

An essential clause cannot be eliminated from a sentence without changing the meaning of the sentence. Essential clauses are never set off from the rest of the sentence with commas.

Example: People who do their dishes tend to be good roommates.

Without the essential clause “who do their dishes,” the sentence just reads, “People tend to be good roommates.” While this is grammatically correct, the writer’s intention in this sentence is to say that people who do their dishes are good roommates, not necessarily all people.

A nonessential clause can be eliminated from a sentence without altering the meaning of the sentence — think of a nonessential clause as bonus info. Nonessential clauses are always set off from the rest of the sentence with commas.

Example: Anna, who always does her dishes, is a good roommate.

In this case, “who always does her dishes” adds an interesting description of Anna. But if you remove this clause from the sentence, the sentence retains its meaning; the reader still understands that Anna is a good roommate.

Other examples:

• The company that invented self-cleaning refrigerators just went public.
• Salesforce, which was founded in 1999, is based in San Francisco.
• That movie that flopped in theaters is now on Netflix.

Legally Blonde, which stars Reese Witherspoon, is on Netflix.