which

whichpronoun

Which either asks someone to choose among known people or things, or links a clause back to something just named.

1. choosing from a known setused alone to ask someone to choose among a limited number of people or things

   Which is used when the possible answers are known or limited, unlike what, which asks a more open question.

   • Which do you prefer, the blue or the green?
   • Which of these bags is yours?
   • I can't decide which to buy.
   • Which is faster, the train or the bus?

   Collocations

   phrase which of

   Compare what (what asks an open question with no limited set of answers in mind); what

2. referring backused to introduce a clause that gives more information about a thing, an idea, or a whole sentence just mentioned

   Which stands for something already named, usually a thing rather than a person (who is used for people). It is the normal choice with a comma before it, adding extra information that could be left out: the book, which I borrowed, is due back. In American English, a clause with no comma normally uses that instead of which. Which can also refer back to a whole idea, not just one noun: He apologized, which surprised everyone.

   • The book, which I borrowed last week, is due back today.
   • She gave me a ring, which I still wear.
   • This is the matter about which we spoke.
   • He forgot my birthday, which hurt my feelings.

   Collocations

   phrase which is why, which means

   Synonyms that (in American English, that is the normal choice for a clause with no comma; which is used mainly for a clause with a comma before it)

   Compare who (who is used for people; which is used for things and ideas)

   For translators (sense 2)

   Grammar trap Many languages have no separate relative pronoun for things versus people, or use the same word both to ask questions and to link clauses; English keeps which apart from who and, in questions, from what.

See also which (which before a noun: which color do you prefer?)

whichdeterminer

1. choosing from a known setused before a noun to ask someone to choose among a limited number of people or things

   Which is used when the possible answers are known or limited, unlike what, which asks a more open question.

   • Which bus goes to the museum?
   • Which color do you prefer, blue or green?
   • Which bag is yours?
   • Which day works best for the meeting?

   Collocations

   phrase which one

   Compare what (what asks an open question with no limited set of answers in mind)

2. referring backused before a noun to refer back to something already mentioned, especially in the phrase in which case

   This use links a fact to what follows: the fact just stated becomes the reason for the next part of the sentence.

   • The meeting may run late, in which case we'll order dinner in.
   • She might be delayed, in which case start without her.
   • The road could flood, in which case take the highway instead.

   Collocations

   phrase in which case, by which time

See also which (which standing alone, or introducing a relative clause: the book, which I loved)