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Comma Before a “Relative Clause”: The Definitive Guide

Comma Before a “Relative Clause”: The Definitive Guide

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Learning English means having the burden of going through grammar whatnots, which includes remembering one too many complex principles.

Plus, concepts being called in multiple variations makes English a huge and bitter pill to swallow. Couldn’t agree more, could you?

One of these things I’m referring to is what we call “relative clauses,” which may or may not need pre-commas.

Now, allow me to take you on an easy, comfortable ride down this seemingly-scary and dark tunnel.


When should we place a comma before a relative clause?

Deciding on whether or not to use a comma before a relative clause, which simply functions like adjectives, lies beneath understanding its importance in light of the whole sentence per se. A defining, also known as either restrictive or essential clause, does not need a pre-comma. Whereas, a non-defining, otherwise called nonrestrictive or inessential clause, is the one that necessitates the comma placement.


What is a relative clause?

A relative clause wears another mask, the “adjective clause,” which makes the concept a bit confusing for some.

Apparently, the main reason behind the name-calling variation is to make the technical-sounding principle seem less taxing.

A teacher’s job is to simplify complex ideas and make them more comprehensible for the learners.

So, we could say that the intention isn’t really that bad after all.

We can, therefore, think of relative clauses as simply adjectives that are much longer than ordinary single-word ones.

Relative clauses are dependent clauses that cannot stand alone, meaning they are like toddlers who need parental guidance all the time.

A relative clause is generally introduced by a relative pronoun in colloquial English.

However, a preposition may also start it off when we need to express our ideas more formally.

These relative clauses are classified into two major categories, the defining and non-defining types.

But, we may also need to take note of another sub-category which, in this post, is named as the “shortened relative clause”.

Let’s now put these clauses under a microscope, shall we?


Defining relative clause

Just like its mother, the “defining relative clause” does have a couple of nicknames as well.

Grammar sticklers call it a restrictive clause, while less technical individuals may refer to it simply as an essential clause.

Again, the reason why it has got its other nicknames is for simplification and better understanding.

So, please don’t ever think again that this concept is obscure, okay?

A defining relative clause, introduced by a relative pronoun, bears some meaning that is of utmost importance to the rest of the sentence.

Relative pronouns are those wh-words that are not used for asking questions, but rather to refer back to another word, a noun, in the same sentence.

The referred noun is called an “antecedent” whose role is to determine the exact relative pronoun to use in the relative clause.

Also, an antecedent may syntactically function as a subject or an object depending on the writer’s intention.

People who commit heinous crimes will be prosecuted.

In the example above, “who commit heinous crimes” is the defining relative clause introduced by the relative pronoun “who.”

“Who,” which is determined by the antecedent “people,” may be replaced with other wh-words depending on the antecedent.

Just like how we value our sense of sight, we don’t want to lose our defining relative clause, or else it wouldn’t be that easy to perceive colors anymore.

The same idea applies to defining relative clauses; removing them makes the sentence unclear, unpredictable, and nonetheless awkward.

Here’s an example to illustrate that using the earlier example.

People will be prosecuted.

Based on the remaining information left, would it be straightforwardly possible to point out who deserves legal proceedings without any other background context?

Of course, not! The sentence’s connotation seems a lot threatening to the human race as a whole, doesn’t it?

The argument above is the exact reason why we need these defining relative clauses in our sentences.

Now, we are going to compare defining relative clauses to the ones that are less important yet still relevant ideas.


Non-defining relative clause

At this point, I’m sure it is going to be easier to make sense of non-defining relative clauses, which are also called nonrestrictive or inessential clauses.

Contrary to the earlier type, a non-defining clause gives additional information about a noun to amplify the meaning of the whole sentence.

This implies that relatively speaking, a non-defining clause has lesser importance than that of a defining clause.

Similar to the defining clause, a non-defining clause may refer to either a noun subject or object in a sentence.

Since the information implied by this type of clause is, albeit interesting, not really that essential as regards the entire sentence.

Hence, it can be conveniently removed without hurting the ego of the sentence’s grammaticality.

In stylistics, we also refer to this type of device as a parenthesis, which is a tool for persuasion or, as I call it, “linguistic sassiness.”

Let me give you another example.

Theodore “Ted” Bundy, who was from Vermont, was prosecuted for committing heinous crimes.

That sentence is more informative rather than threatening, right?

Now, why don’t we remove the relative clause to see why it is classified under the non-defining category.

Theodore “Ted” Bundy was prosecuted for committing heinous crimes.

It is not impossible to know who got into legal proceedings based on the information left, as the sentence would still let you know this clearly.

Once you see these differences over and over in written documents, knowing whether or not to place a pre-relative clause comma should become handy.

Lastly, let’s talk about relative clauses that have been truncated, ellipted, or simply shortened for convenience reasons.


Shortened relative clause

A shortened relative clause could either have a defining or non-defining function, which would also guide the comma placement.

In particular, we may conveniently remove the relative pronoun, especially in spoken English.

More technically, this process is linguistically known as “ellipsis” which is also another stylistic device.

Removing the “understood-by-context” relative pronoun does not lacerate grammaticality, but it reduces the formality level of written sentences.

As you may have known, formal language entails grammatical completeness and strictly adheres to grammatical patterns and principles.

However, in less formal situations, some words can be skipped as long as the hearer or listener would still be able to identify the meaning.

The catch, though, is the relatively higher chances of miscommunication when the interlocutors aren’t on the same page.

Anyway, here are some examples of defining and non-defining relative clauses that have been shortened.


Shortened defining relative clause

One way to reduce the relative clause is by inflecting the verb in its gerund form by adding -ing and omitting the subject pronoun.

In the sentence below, the clause defines the object “people,” which is why it comes at the end of the sentence rather than midway.

I agree with people thinking that coriander tastes like soap.

The next sentence is the complete and unellipted version.

I agree with people who think that coriander tastes like soap.


Shortened non-defining relative clause

For non-defining clauses, the way to cut the sentence is to remove the relative pronoun together with the linking verb.

I live in Utah, the best place for skiing and snowboarding.

And, here is its more complete form.

I live in Utah, which is the best place for skiing and snowboarding.


The essential comma before a relative clause

As stated some sentences ago, a comma is essentially placed before a relative clause whose meaning might be interesting, but not pragmatically significant to the rest of the sentence.

The relative pronouns who, whom, whose, which, and even an omitted pronoun may be used to introduce non-defining relative clauses.

Here are some examples for your reference.


Essential comma before a relative clause starting with “who”

That guy on the corner, who is actually a musician, is one of the performers tonight.


Essential comma before a relative clause starting with “whom”

The one-man band at the subway, whom I think is extremely talented, played my favorite song this morning.


Essential comma before a relative clause starting with “whose”

Jorja Smith, whose skin looks amazing on screen, hits her high notes like only doing her ABCs.


Essential comma before a relative clause starting with “which”

She knows all the songs in Nas and Damian’s Distant Relatives album, which she thinks is one of the best collabs ever done.


Essential comma before a relative clause “without a relative pronoun”

Amy Winehouse, (who is) one of the most celebrated female artists over a decade ago, passed away at the age of 27.


The inessential comma before a relative clause

Paradoxically speaking, the essential information is the one that does not essentialize pre-commas when used in defining relative clauses.

All the relative pronouns used in the previous section can start off defining clauses, with an additional “that.”

This is one important difference between the two types.

Also note that it is only possible to omit relative pronouns that function as the object of the clause rather than the subject.

Here are some examples.


Inessential comma before a relative clause starting with “who”

People who are addicted to coffee don’t mind drinking a cup or two before going to bed.


Inessential comma before a relative clause starting with “whom”

She smirked at the lady whom she thought worked for the shop.


Inessential comma before a relative clause starting with “whose”

A person whose values are not well-defined may think that altruism is fake or even nonexistent.


Inessential comma before a relative clause starting with “which”

The book which is in the bottom drawer has the most fascinating story I’ve ever read.


Inessential comma before a relative clause “without a relative pronoun”

May God bless all those people (who are) having hardships right now.


How do we know whether or not to place a comma before a relative clause?

The easiest trick to knowing the necessity of a pre-comma is to analyze how specific the referred noun or antecedent is.

If the antecedent used is particular enough, for example, a person’s name, the relative clause is generally just information added for emphasis.

This then means that the clause is not grammatically nor pragmatically important, not to mention removable, and thus, requires comma encapsulation.

Otherwise, a vague antecedent that could be just any entity without further details, then no commas are needed since the clause’s meaning is directly attached to the whole sentence.

It’s not necessarily rocket science, right?


Deciding between “that” and “which”

And now, let’s also talk a little bit about one of the biggest questions on relative clauses, the “which” vs “that.”

This dilemma isn’t really that hard to solve either because the same principles apply in determining which pronoun to use.

The little hack here is to simply remember that “which” is applicable in both defining and non-defining clauses, while “that” is only used in the defining type.

The earlier sections, together with our natural pragmatic acuity, would tell us the necessity of the clause.

Therefore, only use “that” when the information included is essential; however, the usage of “which” would be dependent, again, on how specific the antecedent is.


Frequently Asked Questions


What is an example of a relative clause?

“The guy who has the mohawk hairstyle is my brother.” In this sentence, “who has the mohawk hairstyle” is the relative clause classified under the defining or restrictive type. “My brother Patrick, whose hair looks weird, is jobless.” In this sentence, “whose hair looks weird” is a non-defining or nonrestrictive relative clause.


What are the types of relative clauses?

The two main types of relative clauses are defining and non-defining. A defining clause may sometimes be called either a restrictive or essential adjective clause. A non-defining clause is sometimes called a nonrestrictive or inessential adjective clause.


What is the difference between a defining and a non-defining relative clause?

A defining relative clause, also called a restrictive or essential clause, carries essential meaning to the rest of the sentence and does not need any commas. Whereas, a non-defining or nonrestrictive relative clause only contains additional, emphatic information that necessitates comma encapsulation.


When do we need a comma before a relative pronoun?

A comma is necessary before a relative pronoun that introduces a non-defining or nonrestrictive relative clause. This type of clause carries grammatically insignificant meaning to the rest of the sentence.



Getting tripped over grammatical concepts from time to time is a natural event for both native and non-native speakers of English.

But, reading a definitive article or two about these linguistic subtleties only takes a matter of at least three or five minutes.

So instead of just checking bits and pieces of information online, it would be much better to have an in-depth scrolling of these concepts.

Doing this would certainly remove anyone from getting caught in the weeds and more time-efficient in the long run.