An adjective clause is a dependent clause that identifies or adds information about a noun or pronoun. It is also called a relative clause.
Consider:
The parcel that arrived without a return address is still at reception.
The adjective clause identifies which parcel is being discussed. Without it, the sentence tells us that a parcel is at reception but leaves its identity less clear.
Adjective clauses help connect related information without repeating the same noun. Their placement matters, too. A clause attached to the wrong noun can give readers a different impression from the one the writer intended.
What Is an Adjective Clause?
An adjective clause forms part of a larger sentence and has its own grammatical structure.
The engineer who inspected the damaged bridge submitted her report yesterday.
The main statement is that the engineer submitted her report. The clause who inspected the damaged bridge identifies the engineer.
Most adjective clauses appear immediately after the noun or pronoun they modify. Many begin with relative words such as who, which, that, or where, although some defining clauses have no visible introductory relative word.
Because adjective clauses are dependent, they do not normally stand alone as complete sentences.
How Adjective Clauses Modify Nouns and Pronouns
An adjective clause may describe a noun serving as the subject, object, or another part of a sentence. It can also modify a pronoun.
The company replaced the equipment that had repeatedly failed inspection.
The clause identifies the equipment that was replaced.
Anyone who has already registered can collect a visitor pass.
Here, the clause narrows the reference of anyone to people who have registered.
In longer sentences, however, finding the intended noun is not always so straightforward.
When More Than One Noun Could Be Modified
Consider:
The journalist photographed the daughter of the musician who was wearing a red coat.
Who wore the coat: the daughter or the musician?
The clause who was wearing a red coat appears immediately after musician, which favours that interpretation. But a reader may also understand it as referring to daughter.
If the daughter wore the coat, the sentence can be clarified:
The journalist photographed the musician’s daughter, who was wearing a red coat.
If the musician wore it, separating the information removes the uncertainty:
The journalist photographed the musician’s daughter. The musician was wearing a red coat.
Neither revision invents a time relationship or assumes the musician’s gender.
The original sentence is not necessarily ungrammatical. The difficulty is that two possible references compete, leaving the intended meaning uncertain.
Words That Introduce Adjective Clauses
Adjective clauses commonly begin with relative pronouns or relative adverbs. These words connect the clause to the noun it describes.
Relative Pronouns
Who commonly refers to people.
The researcher who developed the new testing method received an award.
Whom is a formal object form, particularly common after prepositions.
The consultant to whom the documents were sent has requested more information.
Whose expresses possession or another close relationship.
The novelist whose manuscript was rejected several times eventually found a publisher.
Which commonly refers to things and animals.
The sculpture, which had been stored for decades, was finally returned to the gallery.
That commonly introduces defining clauses referring to people or things.
The instructions that accompanied the replacement parts were difficult to follow.
The relative pronoun has a role within its clause. For instance, who is the subject of developed, while whom is the complement of the preposition to.
Relative Adverbs
Where commonly introduces clauses modifying places.
The warehouse where the furniture was stored has been converted into offices.
When can introduce a clause modifying a time expression.
The afternoon when the results were announced remains vivid in her memory.
Why can introduce a clause associated with a reason.
The reason why the application was rejected was never fully explained.
These are common ways of introducing adjective clauses, but the introductory word alone does not determine the clause’s function.
Defining and Non-Defining Adjective Clauses
An adjective clause may identify which person or thing is being discussed, or it may add information about someone or something already identified.
That difference determines how the clause is punctuated.
Defining Adjective Clauses
A defining adjective clause, also called a restrictive clause, limits the reference of a noun or pronoun.
The paintings that were damaged during transport were removed from display.
The sentence refers specifically to the paintings damaged during transport. It does not necessarily include paintings that arrived undamaged.
The clause identifies the relevant group, so it is not separated from the noun by commas.
Removing it produces a broader statement:
The paintings were removed from display.
The sentence remains grammatical, but it no longer identifies the same group as precisely.
Non-Defining Adjective Clauses
A non-defining adjective clause, also called a non-restrictive clause, adds information about a person or thing already identifiable from context.
The paintings, which were damaged during transport, were removed from display.
Here, the paintings refers to an already identifiable group. The adjective clause adds the information that they were damaged.
The commas show that the clause supplies additional information rather than identifying particular paintings within a larger group.
A non-defining clause can also interrupt the main sentence:
Elena, who recently completed her apprenticeship, has joined the restoration team.
The clause tells us more about Elena without establishing which Elena is meant.
The distinction is about reference, not simply whether the information seems important. A non-defining clause can contain important facts even though it is not needed to identify the person or thing being discussed.
Two Important Punctuation Rules
That is not used to introduce an ordinary non-defining relative clause.
Incorrect: The collection, that was donated last year, is now on display.
Correct: The collection, which was donated last year, is now on display.
The introductory relative word also cannot normally be omitted from a non-defining clause.
The final draft, which the editor approved yesterday, is ready for printing.
Removing which would not produce a grammatical non-defining relative clause.
When Can the Relative Pronoun Be Omitted?
In some defining adjective clauses, a relative pronoun can be left out when it functions as the object of a verb or preposition.
Consider:
The documentary that Maya recommended won an award.
Here, that represents the documentary as the object of recommended.
The sentence remains grammatical without it:
The documentary Maya recommended won an award.
The situation changes when the relative pronoun is the subject of its clause.
The neighbours who reported the leak contacted the landlord again.
Who is the subject of reported.
Removing it would make the intended construction ungrammatical.
Incorrect: The neighbours reported the leak contacted the landlord again.
Correct: The neighbours who reported the leak contacted the landlord again.
An object relative pronoun can often be omitted from a defining clause, but a subject relative pronoun normally cannot.
Using Adjective Clauses to Make Writing Clearer
An adjective clause can bring related information together neatly. But combining sentences is not always the clearest choice, particularly when several nouns or modifying clauses appear close together.
Combining Related Information
Suppose you have two statements:
A contractor inspected the roof yesterday.
The contractor had repaired the same roof five years earlier.
They can be combined:
The contractor who had repaired the roof five years earlier inspected it again yesterday.
The clause identifies the contractor without repeating the noun.
This arrangement preserves both the earlier repair and the later inspection.
Keeping the Clause With the Intended Noun
Consider:
The gallery displayed the sketches beside the portraits that had been restored.
As written, the adjective clause naturally modifies portraits.
But suppose the sketches were restored instead.
The sentence should be revised:
The gallery displayed the sketches that had been restored beside the portraits.
Now the clause identifies the sketches.
The original wording was grammatically possible, but it suggested a different meaning. Placing the clause closer to the intended noun resolves the problem.
When Separate Sentences Work Better
A sentence can become difficult to follow when several modifying clauses are nested within one another.
The coordinator who supervised the volunteers who managed the registration desk sent the revised schedule.
Both clauses are grammatical, but the reader must follow two layers of information before reaching the main action.
A clearer alternative is:
The volunteers managed the registration desk. The coordinator who supervised them sent the revised schedule.
This preserves the relationships without adding an unsupported sequence of events.
There is nothing inherently wrong with using more than one adjective clause in a sentence. Separating the information becomes useful when the combined structure makes those relationships unnecessarily difficult to follow.
Adjective Clause vs. Adjective Phrase and Other Clauses
Adjective clauses can resemble other grammatical structures, especially when they occupy similar positions or begin with the same word.
Adjective Clause vs. Adjective Phrase
Compare:
The passengers who were anxious about the delay approached the service desk.
The passengers anxious about the delay approached the service desk.
The first highlighted construction is an adjective clause. It contains the subject who and the finite verb were.
The second is an adjective phrase headed by anxious.
Both describe the passengers, but their internal structures differ.
Adjective Clause vs. Noun Clause
Consider:
We remembered where the documents were stored.
The highlighted clause supplies the content of what was remembered. It is an embedded interrogative content clause.
Now compare:
The cabinet where the documents were stored was locked.
Here, the same words modify cabinet, making the construction an adjective clause.
Adjective Clause vs. Adverbial Clause
Consider:
The staff left when the inspection ended.
The dependent clause explains when the staff left. It is adverbial.
Now compare:
The day when the inspection ended was unusually cold.
Here, the clause modifies day, so it is adjectival.
The relationship between the clause and the surrounding sentence determines its function.
Adjective Clauses: Practice With Answers
1. Identify the Intended Noun
A writer intends to say that a painting, rather than its frame, was damaged.
The curator examined the frame of the painting that had been damaged.
Rewrite the sentence to make the intended reference clear.
Possible answer:
The curator examined the frame of the damaged painting.
The adjective damaged now clearly describes the painting.
Although the revision no longer uses an adjective clause, it expresses the intended meaning without leaving the reader to decide whether the frame or painting was damaged.
2. How Do Commas Change the Meaning?
Compare:
A. The applicants who completed the practical test were invited back.
B. The applicants, who completed the practical test, were invited back.
Answer:
In A, the defining clause identifies the applicants who completed the test. It does not establish whether other applicants were invited back.
In B, the applicants refers to an already identifiable group. The non-defining clause adds the information that they completed the test.
The difference is grammatical and meaningful, not merely a punctuation preference.
3. Can the Relative Pronoun Be Omitted?
Which sentence can omit the highlighted relative pronoun?
A. The records that the archivist examined were badly damaged.
B. The archivist who examined the records recommended special storage.
Answer: Sentence A.
In A, that represents the object of examined:
The records the archivist examined were badly damaged.
In B, who is the subject of examined, so it cannot be omitted from that construction.
4. Resolve the Ambiguous Reference
A writer intends to say that the teacher, not the student, was carrying a red folder.
The principal spoke to the student of the teacher who was carrying a red folder.
Rewrite the sentence so the intended meaning is clear.
Possible answer:
The principal spoke to the teacher’s student. The teacher was carrying a red folder.
Separating the information identifies who carried the folder without introducing unnecessary assumptions.
5. Revise Without Changing the Facts
Original:
The technicians who inspected the equipment that had been damaged during the storm submitted their findings.
Which revision preserves the information while reducing the layers of modification?
A. The technicians inspected the storm-damaged equipment and later submitted their findings.
B. The equipment had been damaged during the storm. The technicians who inspected it submitted their findings.
Answer: B.
The second revision preserves the information about the equipment and the technicians without introducing an additional time relationship.
Sentence A adds later, which explicitly establishes a sequence not stated in the original sentence.
The First English Grade Editorial creates simple English grammar, vocabulary, and language guides for students, beginners, and everyday learners.