Non-defining Adjective Clauses — General

There are two kinds of adjective clauses in English: defining and non-defining. This lesson explains non-defining adjective clauses.

What's a non-defining adjective clause?

First, some examples:

Example Adjective clause Comments
Canada, which is located north of the USA, has a long winter. which is located north of the USA The clause describes “Canada”. It gives us extra information about Canada.
William Shakespeare, who lived over four hundred years ago, wrote the most famous plays in the English language. who lived over four hundred years ago The clause describes “William Shakespeare”, and gives us extra information about him.

Please notice how the non-defining adjective clause gives extra information about the noun it describes. It doesn't tell us which one we're talking about — in the examples above, everybody knows “Canada” and “William Shakespeare”, so it doesn't define them.