Elizabeth O'Brien

Hello! I'm Elizabeth O'Brien, and my goal is to get you jazzed about grammar. 

Adjective Clauses

Adjective clauses (or relative clauses) are a type of subordinate clause that act as adjectives. The whole clause does the job of an adjective.

Quick Refresher

Take a look at this sentence.

The happy woman danced across the street.

Happy is a word. It is an adjective modifying the noun woman. It is telling us which woman. (Which one is an adjective question.) Which woman? The happy woman.

Even if you don't know anything about diagramming sentences, it's easy to see in the following sentence diagram that the word happy is modifying the word woman - it's branching right off woman!

sentence diagram of an adjective

Now, look at this sentence.

The woman who looked happy danced across the street.

This time, we have a whole clause doing the job of an adjective! The whole clause who looked happy is modifying the noun woman. It contains a subject (who) and a verb (looked), and it is answering the adjective question which one. Which woman? The woman who looked happy.

The whole clause is acting as one part of speech - an adjective. Because of this, we call it an adjective clause.

Now take a look at the diagram of this sentence. You can see that who looked happy is modifying the noun woman. It looks a bit different than the diagram above, but just like with the adjective happy, the clause who looked happy is branching off woman.

sentence diagram of an adjective clause

Here's a picture to summarize what we've covered so far.

What is an adjective clause?

Relative Pronouns Can Introduce Adjective Clauses

Most of the time, relative clauses are introduced by certain words called relative pronouns.

who, whom, whose, that, which

  • The person who made the mess needs to clean it. (The clause is modifying person.)
  • The girl whom you teach is my sister. (The clause is modifying girl.)

  • People whose cats shed need to vacuum often. (The clause is modifying people.)

  • This is the house that Jack built. (The clause is modifying house.)

  • The book which I had not read fell on my head. (The clause is modifying book.)

Relative pronouns link the clause with the word that the clause is modifying. Did you notice that the noun that comes directly before the clause is the noun that the clause is modifying? Good. I'm glad that you saw that. :)

The cool thing about relative pronouns is that they also act as the subject, object, or some kind of modifier within the adjective clause. Let's use this sentence as an example.

This is the house that Jack built.

The independent clause is This is the house. The relative clause is that Jack built. Notice that both clauses have a subject and a verb. That is introducing the relative clause. It is linking the word house with the whole clause. That is also acting as the direct object within the clause.

Jack = subject, built = verb, that = direct object

Look at the sentence diagram, and it will help you see what I mean.

Sentence diagram of an adjective clause with a relative pronoun

You'll find more information and sentence diagrams on the relative pronouns page.

No Relative Pronoun?

Sometimes the relative pronoun is missing from the relative clause. Don't fret! You can still have an adjective clause without the relative pronoun. Here is an example of a sentence with the relative pronoun that.

  • The instrument that I love is the piano.

The adjective clause is that I love.

Can you think of how you could express that same idea without the relative pronoun?

  • The instrument I love is the piano.

Now the adjective clause is just the words I love, but the word that is implied. It's as if the sentence says:

  • The instrument (that) I love is the piano.

Whenever words are implied in a sentence, it is called an elliptical. The technical name for a missing relative pronoun is an elliptical relative pronoun. If you want to diagram the sentence, diagram the implied relative pronoun in parentheses.

Relative Adverbs

While most of the time relative clauses are introduced by relative pronouns, sometimes they are introduced by relative adverbs (where, when, why). Here are some examples. Notice that the clause is still modifying a noun.

  • This is the park where we played.

  • Tuesday is the day when we have pizza for dinner.

  • Our teacher told us the reason why we study grammar.
Sentence diagram of an adjective clause with a relative adverb
Sample video lesson of the Get Smart Grammar Program

Psst! Learn more about adjective clauses with this sample lesson from our Get Smart Grammar Program.

Elizabeth O'Brien from Grammar Revolution

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I hope this lesson helped you learn about relative clauses!

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Elizabeth O'Brien

Elizabeth O'Brien is the creator of Grammar Revolution.

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Other Helpful Resources

You're so smart! If you want to test your skills, check out the page on diagramming relative pronouns.

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