who

who — pronoun

1. the question word you use when you want to know the identity, name, or role of a

1.pronounA1
Definition

the question word you use when you want to know the identity, name, or role of a person — for example, asking who called, who someone is, or who someone came with

Example

Who is the woman standing next to the window?

who + be + noun phrase (asking identity)

Who called Élise on the phone while she was cooking dinner?

Grammar Patterns

who + verb

who + auxiliary + subject + verb

Usage Note

In informal spoken English, "who" is used for both the subject and object of a verb. In formal writing, "whom" is sometimes used when "who" is the object.

Common Mistakes

Who you met at the station?
Who did you meet at the station?
In questions, add an auxiliary verb (did/do/does) when 'who' is the object.

2. used by a person in authority, such as a guard or official, to ask someone arriv

2.pronounB1
Definition

used by a person in authority, such as a guard or official, to ask someone arriving at a place to give their name and state their business

Example

The night guard shouted into the darkness, 'Who goes there?'

authority challenge: 'Who goes there?'

A voice from behind the locked door asked, 'Who is it?'

Grammar Patterns

who + auxiliary + subject (+ to-infinitive)

Usage Note

This sense is often found in fixed expressions ('Who goes there?') and in contexts involving security or restricted access. The structure is usually a direct question with no auxiliary inversion needed when 'who' is the subject.

3. appears with verbs about knowledge or awareness — such as 'know', 'remember', 'w

3.pronounA2
Definition

appears with verbs about knowledge or awareness — such as 'know', 'remember', 'wonder', or 'forget' — in contexts where the answer is unclear or has not yet been discovered

Example

I do not know who sent this package to our office.

know + who + clause (uncertainty)

Nobody can remember who first told that joke during the meeting.

Grammar Patterns

know/remember/understand/forget + who + clause

Usage Note

Common with verbs like know, remember, forget, understand, wonder, and figure out. This is a 'content clause' use of 'who' — it introduces a clause that tells what is not known. The clause after 'who' uses normal statement word order, NOT question word order.

Common Mistakes

I do not know who is he.
I do not know who he is.
After 'who' in a statement, use normal subject-verb order, not question order.

4. links a previously mentioned person to a description that identifies them — for

4.pronounA2
Definition

links a previously mentioned person to a description that identifies them — for instance, 'the woman who called' connects 'woman' with the action of calling. Only applies to people, never to objects or animals.

Example

The woman who lives next door works as a nurse at the city hospital.

who as subject of relative clause

The teacher who Yuki admired most retired at the end of last year.

who as object of relative clause

Synonyms
  • that

    Informal alternative in defining relative clauses; can refer to both people and things

  • whom

    Formal object form, used instead of 'who' when it is the object of the verb or preposition

Antonyms
  • which

    Used for things and animals, not people

Grammar Patterns

noun + who + verb (subject)

noun + who + subject + verb (object)

Usage Note

Use 'who' for people and 'which' or 'that' for things. In defining (restrictive) clauses, 'who' identifies which person you mean. In non-defining (non-restrictive) clauses, 'who' adds extra information and is set off by commas. In informal English, 'that' can replace 'who' in defining clauses.

Common Mistakes

The book who I read was interesting.
The book that I read was interesting.
Use 'who' for people, not for things or objects.
Idioms

who — noun

Word family

Synonym discussion

Sense: pronoun/4

All four words can introduce relative clauses, but they differ in usage. 'Who' refers to people and works as both subject and object in everyday English ('the woman who called'). 'Whom' is the formal object form ('the woman whom I called'), but it is becoming rare in speech and many writers now use 'who' in object position. 'That' is a versatile alternative for both people and things in defining clauses ('the woman that called'), though it cannot follow a preposition directly or begin a non-restrictive (comma) clause. 'Which' is used only for things and animals ('the book which I read'), never for people. In non-defining clauses — those set off by commas that add extra information — 'who' and 'which' are used but 'that' is not: 'My sister, who lives in Taipei, is a doctor.'

who ↗whom ↗that ↗which ↗

Etymology

Proto-Indo-EuropeanProto-GermanicOld EnglishMiddle EnglishEnglish

From Old English 'hwā' (interrogative pronoun), tracing back through Proto-Germanic '*hwas' / '*hwō' to the Proto-Indo-European root '*kʷos' / '*kʷis', which also produced Latin 'quis' (who?) and Sanskrit 'káḥ' (who?). The word has served as an interrogative pronoun for over a thousand years in English, with its basic form changing surprisingly little.