A relative pronoun connects a dependent relative clause to a noun or pronoun in a main clause while taking a grammatical role inside that clause. The main English relative pronouns are who, whom, whose, which, and that; their correct choice depends on the antecedent, the pronoun’s subject or object role, and whether the clause is essential.
Key Facts at a Glance
- A relative pronoun links a relative clause to an antecedent and replaces a repeated noun inside that clause.
- Who normally refers to people as subjects, while whom refers to people as objects in formal English.
- Whose expresses possession and can modify people, animals, organizations, and things.
- That introduces restrictive clauses in standard American usage and takes no comma.
- Which commonly refers to things or animals; nonrestrictive which clauses require commas.
- A relative pronoun can be omitted only when it functions as the object, not when it functions as the subject.
What Is a Relative Pronoun?
A relative pronoun is a pronoun that introduces a relative clause and connects that clause to an antecedent. The antecedent is the noun or pronoun being described, while the relative clause supplies information about it.
In The engineer who designed the bridge won an award, engineer is the antecedent and who designed the bridge is the relative clause. The word who performs two jobs: it refers back to engineer, and it acts as the subject of designed. Relative clauses usually function like adjectives because they modify nouns.
Relative pronouns prevent repetition. The two sentences The engineer designed the bridge and The engineer won an award can become The engineer who designed the bridge won an award. The resulting sentence contains one main clause and one dependent clause, joined through a shared reference.
What Is the Antecedent?
The antecedent is the noun that a relative pronoun represents or modifies. A relative pronoun should normally appear close to its antecedent so readers can identify the intended connection without rereading the sentence.
| Sentence | Relative pronoun | Antecedent | Role in clause |
|---|---|---|---|
| The nurse who called is waiting. | who | nurse | Subject |
| The nurse whom I called is waiting. | whom | nurse | Object |
| The company whose website changed hired a designer. | whose | company | Possessive determiner |
| The device which failed needs testing. | which | device | Subject |
| The device that I repaired works now. | that | device | Object |
A relative pronoun does not always represent the same grammatical role as its antecedent has in the main clause. In The manager whom the employees respected retired, manager is the subject of retired, but whom is the object of respected.
How Do Relative Pronouns Work?
Relative pronouns work by combining a main clause with a dependent clause that modifies a noun. The pronoun points backward to the antecedent and simultaneously fills a missing subject, object, or possessive position in the relative clause.
Use this four-step process:
- Find the antecedent. Decide whether the clause describes a person, thing, animal, organization, or place.
- Inspect the relative clause. Determine whether the pronoun performs the action or receives it.
- Decide whether the information is essential. Essential information is restrictive; optional information is nonrestrictive.
- Check attachment and punctuation. Place the clause beside its antecedent and use commas when the clause is nonrestrictive.
For example, The researcher who developed the vaccine received funding contains who developed the vaccine. The researcher is the antecedent, who is the subject of developed, and the clause identifies which researcher received funding.
Subject or Object: The Fastest Test
A relative pronoun is a subject when it performs the verb’s action. A relative pronoun is an object when another subject performs the action toward it.
| Role | Example | Complete underlying idea | Pronoun removable? |
|---|---|---|---|
| Subject | The student who answered smiled. | She answered. | No |
| Object | The student whom I helped smiled. | I helped her. | Yes, in informal style |
| Subject | The car that stopped blocked traffic. | It stopped. | No |
| Object | The car that I sold was electric. | I sold it. | Yes |
| Possessive | The author whose book won spoke. | The book belongs to the author. | No |
The simplest practical test is to supply a personal pronoun. If he or they fits, choose who; if him or them fits, formal English uses whom. In the candidate whom we interviewed, the hidden sentence is we interviewed him, so whom is grammatically objective.
Which Relative Pronoun Should You Use?
The correct relative pronoun depends on antecedent type, grammatical role, clause type, and register. The table below gives the standard choices, but real usage also varies between American, British, formal, and conversational English.
| Pronoun | Typical antecedent | Clause role | Typical clause | Example |
|---|---|---|---|---|
| who | Person | Subject | Restrictive or nonrestrictive | The doctor who treated me called. |
| whom | Person | Object | Restrictive or nonrestrictive | The doctor whom I thanked smiled. |
| whose | Person, animal, thing, organization | Possessive | Restrictive or nonrestrictive | The firm whose data leaked apologized. |
| which | Thing or animal | Subject or object | Usually nonrestrictive in American style | The machine, which was old, failed. |
| that | Person, thing, animal | Subject or object | Restrictive | The machine that failed needs repair. |
When Should You Use Who?
Use who when the antecedent is a person and the pronoun is the subject of the relative clause. Both restrictive and nonrestrictive clauses can use who: The athlete who trained hardest won, and Maya, who trained daily, won.
Conversational English frequently uses who where formal grammar would use whom. The sentence Who did you invite? is standard and natural in ordinary speech, although Whom did you invite? remains the formal objective version. Do not replace who with whom merely because the sentence sounds formal; identify the role first.
When Should You Use Whom?
Use whom when a person is the object of a verb or preposition in formal English. Examples include The client whom we contacted replied and The consultant with whom we worked moved abroad.
Modern English often replaces whom with who, especially when the preposition appears at the end: Who did you work with? This form is widely accepted in conversation and general professional writing. Retain whom in formal notices, legal prose, traditional academic style, and fixed expressions such as To whom it may concern.
| Formal construction | Conversational alternative | Hidden test |
|---|---|---|
| The person whom I called | The person who I called | I called him |
| The colleague with whom I worked | The colleague who I worked with | I worked with him |
| Whom did you consult? | Who did you consult? | You consulted him |
| The expert to whom we wrote | The expert who we wrote to | We wrote to him |
When Is Whose Correct?
Use whose to show possession or association. Although many learners associate whose only with people, standard English also permits it with animals, organizations, and things: a company whose profits increased, a tree whose branches blocked the road, and a device whose battery failed.
Whose is different from who’s. Whose means “belonging to whom” or “of which,” while who’s is a contraction of who is or who has.
- The manager whose office is upstairs is away.
- Who’s responsible for the delay?
- The supplier, whose contract expired, changed its terms.
Avoid forcing the awkward phrase of which when whose provides a clearer possessive relationship.
What Is the Difference Between Restrictive and Nonrestrictive Clauses?
A restrictive relative clause identifies which noun the writer means and takes no commas. A nonrestrictive relative clause adds optional information and must be separated with commas.
Compare these sentences:
- The employees who completed the training received certificates.
- The employees, who completed the training, received certificates.
The first sentence may mean that only the employees who completed training received certificates. The second presents completion as information about all the employees under discussion. Commas can therefore change the factual implication, not merely the rhythm.
| Clause type | Information value | Commas | Common pronouns | Example |
|---|---|---|---|---|
| Restrictive | Identifies or limits the noun | No | who, whom, that, which in some varieties | Books that explain syntax help learners. |
| Nonrestrictive | Adds optional information | Yes | who, whom, whose, which | This book, which explains syntax, is useful. |
| Restrictive after indefinite noun | Narrows a general noun | No | who, that, which | Anyone who applies must register. |
| Nonrestrictive proper name | Adds background information | Yes | who, whose, which | Dr. Chen, who teaches linguistics, wrote it. |
Can You Use That in a Nonrestrictive Clause?
No. Standard edited English does not use that in a nonrestrictive clause. Write The laptop, which I bought in June, is already slow, not The laptop, that I bought in June, is already slow.
In American English, that is the usual choice for many restrictive clauses involving things: The report that I submitted was accepted. British English permits which in restrictive clauses more freely, as in The report which I submitted was accepted. The comma rule still matters in both varieties.
When Can You Omit a Relative Pronoun?
You can omit a relative pronoun when it functions as the object of the relative clause. You cannot omit it when it functions as the subject or when it expresses possession.
- The film that I watched was excellent.
- The film I watched was excellent.
Here, I is the subject and watched needs an object, so that can disappear. By contrast, The film that won the award was excellent cannot become The film won the award was excellent, because that is the subject of won.
Prepositions create another choice:
- The person to whom I spoke is formal.
- The person who I spoke to is conversational.
- The person I spoke to omits the object pronoun.
Do not omit the pronoun from the person who spoke to me, because who performs the speaking.
How Do Relative Pronouns Compare With Other Relative Words?
Relative pronouns are not interchangeable with every word that introduces a dependent clause. Relative adverbs and the word what perform related but different functions.
| Word | Refers to | Main function | Example |
|---|---|---|---|
| who | Person | Subject or object | The pilot who landed safely called. |
| which | Thing or animal | Subject or object | The plane which landed was damaged. |
| that | Person or thing | Restrictive subject or object | The plane that I flew was small. |
| where | Place | Relative adverb | The airport where we landed closed. |
| when | Time | Relative adverb | The year when she graduated was difficult. |
| what | Unstated thing | Fused relative construction | I understand what you mean. |
A relative pronoun has an antecedent. What does not: what you mean means “the thing that you mean.” Writing the thing what you mean is incorrect in standard English because the noun already supplies an antecedent.
How Do You Build a Sentence With a Relative Pronoun?
Build a relative-pronoun sentence by identifying the repeated noun, replacing the second occurrence with the appropriate pronoun, and attaching the resulting clause directly to the first noun.
Start with:
- The architect designed the museum.
- The architect won the competition.
The repeated noun becomes who because it is the subject of won: The architect who won the competition designed the museum.
For an object, use:
- I read the article.
- The article explained clause structure.
The combined sentence is The article that I read explained clause structure. The article is the object of read, so The article I read explained clause structure is also grammatical.
A useful editing checkpoint is to expand the relative clause mentally. If the expanded version has a subject before the verb, the relative pronoun is often an object and may be omitted. If no other subject appears, the relative pronoun is probably the subject and must remain.
What Common Relative-Pronoun Errors Should You Fix?
The most frequent errors involve case, commas, antecedent attachment, and confusion between possessive forms. Each error can be diagnosed by expanding the relative clause or testing whether the clause changes the noun’s identity.
1. Confusing Who and Whom
Incorrect for formal grammar: The analyst who we hired starts Monday.
Formal correction: The analyst whom we hired starts Monday.
The informal version is common and acceptable in many contexts. The formal test is we hired him, not he hired us, so whom is the objective form.
2. Using Commas Around Essential Information
Incorrect meaning: The customers, who submitted receipts, received refunds.
Restrictive correction: The customers who submitted receipts received refunds.
The comma version implies that all relevant customers submitted receipts. Remove the commas when receipt submission identifies the customers who received refunds.
3. Using That After a Comma
Incorrect: The software, that manages payroll, crashed.
Correction: The software, which manages payroll, crashed.
A nonrestrictive clause requires which, who, whom, or whose, depending on its role and antecedent.
4. Creating a Misplaced Modifier
Ambiguous: We found a fault in the network that caused the outage.
The relative clause may appear to modify network or fault. A clearer version is We found a fault that caused the outage in the network or In the network, we found a fault that caused the outage.
5. Confusing Whose and Who’s
Incorrect: The researcher who’s findings changed the field spoke.
Correction: The researcher whose findings changed the field spoke.
Use who’s only when who is or who has fits: The researcher who’s speaking is available means who is speaking.
6. Omitting a Subject Relative Pronoun
Incorrect: The technician repaired the unit failed.
Correction: The technician repaired the unit that failed.
The unit performed the action failed, so the subject relative pronoun cannot be removed.
Are Relative Pronouns Different in Formal and Informal English?
Formal English preserves more distinctions, especially the distinction between who and whom, while informal English often uses who and omits object pronouns. Both registers can be grammatical when their punctuation, clause structure, and meaning are clear.
| Situation | Preferred formal form | Common informal form |
|---|---|---|
| Object of verb | The person whom I contacted | The person who I contacted |
| Object after preposition | The person to whom I wrote | The person who I wrote to |
| Restrictive thing clause | The file that I opened | The file I opened |
| Nonrestrictive thing clause | The file, which I opened, was corrupted | Same form |
| Possession | The firm whose policy changed | Same form |
Professional writers should prioritize clarity over artificial formality. An incorrectly applied whom can make a sentence less readable, while a correctly structured sentence ending in a preposition can be perfectly clear.
How Long Does It Take to Learn Relative Pronouns?
A typical learner can understand the core distinction between who, which, and that in 30-60 minutes, while reliable control of whom, commas, omission, and preposition placement often takes 3-5 hours of deliberate practice.
Learning time varies with a learner’s first language and writing needs. French and Spanish learners may transfer a single relative form such as que across several English roles; German learners may need extra practice with case and clause structure. The most efficient sequence is subject versus object, restrictive versus nonrestrictive, and then formal register.
A practical 10-minute review routine is:
- Mark the antecedent in five sentences.
- Underline the verb inside each relative clause.
- Identify the clause subject.
- Test whether the pronoun can be replaced by he or him.
- Add or remove commas according to meaning.
- Rewrite one sentence with the object pronoun omitted.
Grammar learning has no monetary “cost” in the sense implied by a commercial comparison. The relevant costs are study time, revision time, and cognitive load during editing.
What Should Writers Use in Academic, Business, and ESL Contexts?
Academic writers should preserve distinctions that clarify logic, business writers should reduce avoidable complexity, and ESL learners should master clause roles before memorizing style preferences. The best choice is the form that accurately identifies the antecedent and makes the intended meaning easy to recover.
- Academic writing: Use commas carefully, preserve nonrestrictive distinctions, and use whom when formal case marking improves precision.
- Business writing: Prefer short, direct clauses, but do not delete an object pronoun if omission creates ambiguity.
- Legal writing: Check whether a restrictive clause changes the scope of an obligation, exception, or definition.
- ESL writing: Begin with who for people, which for things, and that for restrictive clauses, then add exceptions through sentence analysis.
- Conversational writing: Who commonly replaces whom, and object pronouns are frequently omitted.
Relative pronouns are not good tools for compressing every sentence. Several consecutive relative clauses can create heavy noun phrases, especially in contracts and technical instructions. Splitting a sentence may improve comprehension when a clause exceeds 15-20 words or contains multiple embedded clauses.
Relative Pronoun Examples by Function
Examples become easier to evaluate when each pronoun’s function is visible rather than memorized as an isolated rule.
| Function | Example | Explanation |
|---|---|---|
| Person as subject | The surgeon who led the team published the results. | Who performs led. |
| Person as object | The surgeon whom the committee honored spoke. | The committee honored him. |
| Thing as subject | The sensor that detects motion saves power. | That performs detects. |
| Thing as object | The sensor that I installed saves power. | I installed it. |
| Possession | The sensor whose battery failed stopped working. | The battery belongs to the sensor. |
| Nonrestrictive thing | The sensor, which was inexpensive, worked well. | The clause adds optional information. |
| Place | The lab where we tested it closed. | Where means “in which.” |
| Time | The day when testing began was rainy. | When means “on which.” |
The examples also show why antecedent type alone cannot determine the answer. A thing can take that, which, or whose, depending on clause function and whether the information is restrictive.
Frequently Asked Questions
Can That Refer to a Person?
Yes. That can refer to a person in a restrictive relative clause, especially in informal and neutral English: The teacher that helped me still works here. Many formal writers prefer who for people, but that is grammatical when the clause identifies which person is meant and has no surrounding commas.
Is Whom Becoming Obsolete?
Whom is less common in conversation but remains active in formal writing, fixed expressions, and constructions after fronted prepositions. Writers do not need to use whom everywhere. Use the objective form when formal precision matters, and use who when the conversational register or sentence rhythm makes that choice more natural.
Can Which Refer to a Person?
Standard modern English normally uses which for things, animals, or an entire preceding idea, not for individual people. Write The employee who called rather than The employee which called. In some specialized or older constructions, which may refer to a group or institution, but who is clearer for human individuals.
Should a Relative Clause Always Come Immediately After Its Noun?
A relative clause should normally follow its antecedent immediately because distance can create ambiguity. Writers can move the surrounding phrase instead: We discovered a defect in the coating that caused corrosion is less clear than We discovered a coating defect that caused corrosion.
What Is a Compound Relative Pronoun?
Forms such as whoever, whomever, whatever, and whichever combine a relative meaning with an indefinite meaning. Whoever finishes first may leave means “any person who finishes first.” These forms are useful when the antecedent is not a known, specific noun.
Do Relative Pronouns Agree With the Verb?
Relative pronouns do not show ordinary singular or plural agreement in the way personal pronouns do, but the verb must agree with the antecedent when the antecedent controls the clause. Write The employee who works remotely and The employees who work remotely, not employees who works.
The Bottom Line
Relative pronouns connect a dependent clause to an antecedent while serving as a subject, object, or possessive marker inside that clause. Choose who for a person acting, whom for a person receiving an action in formal English, whose for possession, which for things and nonrestrictive information, and that for many restrictive clauses. Test the clause, check the commas, and place the modifier beside its noun. Understanding relative pronouns definition usage and examples becomes practical once every choice is tied to grammatical role and sentence meaning.
