Advanced Grammar
Defining and Non-Defining Relative clauses
Recall: we use relative sentences to add information about the subject or object of a
sentence.
There are two types of relative clauses: defining and non-defining.
A defining relative clause gives essential information about the thing or person we are
talking about. In this case, we do not use a comma. The purpose of a defining relative
clause is to clearly define who or what we are talking about. Without this information, it
would be difficult to know what is meant.
• ‘The man who lives across the street in the house with the blue door has been
accused of murder.’ (The information ‘who lives across the street in the house with
the blue door’ is essential since it means that I am talking about only the man who
lives there and no one else)
A non-defining relative clause gives information that is simply additional about the things
or person we are talking about. The additional information is not essential to understanding
the meaning of the sentence. The extra information is put between commas.
• ‘Writer John Doe, who went to the same university as me, has written his first
best selling novel.’ (This gives extra information about John Doe but it is not
essential)
Here are some examples of defining and non-defining relative clauses taken from the article
‘The curious case of Wikileaks and Julian Assange’:
• He was talking about the Wikileaks affair and its leader, Julian Assange, an excomputer hacker who has recently been at the center of global news with a
story that is so strange it could be fiction. (Defining = it gives information
that is essential to the meaning of the sentence)
• It began with Wikileaks - Assange’s website that leaks secret and highly
confidential documents, belonging to governments and other
organizations, onto the internet for anyone to see. (Defining = it gives
information that is essential to the meaning of the sentence)
• Assange and his lawyers argue that the sexual allegations are part of a
politically motivated conspiracy or smear campaign against him, and that the
two Swedish women in question, who he had brief affairs with, consented to
have sex with him. (Non-defining = the information between commas is extra
and it just provides extra information which is not essential to understand the
meaning of the sentence)