which

[ wich, hwich ]

pronoun

1. what one?:

   Which of these do you want? Which do you want?

2. whichever; any one that:

   Choose which appeals to you.

3. (used relatively in restrictive and nonrestrictive clauses to represent a specified antecedent):

   The book, which I read last night, was exciting. The socialism which Owen preached was unpalatable to many. The lawyer represented five families, of which the Costello family was the largest.

4. (used relatively in restrictive clauses having that as the antecedent):

   Damaged goods constituted part of that which was sold at the auction.

5. (used after a preposition to represent a specified antecedent):

   the horse on which I rode.

6. (used relatively to represent a specified or implied antecedent) the one that; a particular one that:

   You may choose which you like.

7. (used in parenthetic clauses) the thing or fact that:

   He hung around for hours and, which was worse, kept me from doing my work.

8. Nonstandard. who or whom:

   a friend which helped me move; the lawyer which you hired.

adjective

1. what one of (a certain number or group mentioned or implied)?:

   Which book do you want?

2. whichever; any that:

   Go which way you please, you'll end up here.

3. being previously mentioned:

   It stormed all day, during which time the ship broke up.

which

/ wɪtʃ /

determiner

1. 1. used with a noun in requesting that its referent be further specified, identified, or distinguished from the other members of a class

      which house did you want to buy?

   2. ( as pronoun )

      which did you find?

   3. ( used in indirect questions )

      I wondered which apples were cheaper

2. 1. whatever of a class; whichever

      bring which car you want

   2. ( as pronoun )

      choose which of the cars suit you

3. used in relative clauses with inanimate antecedents

   the house, which is old, is in poor repair

4. as; and that: used in relative clauses with verb phrases or sentences as their antecedents

   he died of cancer, which is what I predicted

5. the which archaic.
   a longer form of which, often used as a sentence connector

Usage Note

The relative pronoun which refers to inanimate things and to animals: The house, which we had seen only from a distance, impressed us even more as we approached. The horses which pulled the coach were bay geldings. Formerly, which referred to persons, but this use, while still heard ( a man which I know ), is nonstandard. Contrary to the teachings of some usage guides, which introduces both restrictive and nonrestrictive clauses. The “rule” that which can be used only with nonrestrictive clauses has no basis in fact. In edited prose three-fourths of the clauses in which which is the relative pronoun are restrictive: A novel which he later wrote quickly became a bestseller. that.

Usage

See that

Word History and Origins

Origin of which¹

First recorded before 900; Middle English; Old English hwilc, hwelc, equivalent to hwe-, base of hwā interrogative pronoun, + -līc “body, shape, kind”; cognate with Old Frisian hwelik, Dutch welk, German welch, Gothic hwileiks literally, “of what form”; who, like ¹

Word History and Origins

Origin of which¹

Old English hwelc, hwilc; related to Old High German hwelīh (German welch ), Old Norse hvelīkr, Gothic hvileiks, Latin quis, quid

Idioms and Phrases

• every which way
• know which side of bread is buttered
• (which) way the wind blows

Example Sentences

This research is one of several discoveries on African chemical compounds that came from the collaboration between Wistar and the University of Buea Centre for Drug Discovery, which began in 2021.

From Science Daily

One possible explanation is that these drugs increase the risk of microbleeds in the brain, which are associated with cognitive decline.

From Science Daily

It also provided information about the relative abundance of every mRNA copy, which gives clues as to how much a gene is expressed in different tissues and times.

From Science Daily

The work stoppage, which affects service and patient care workers at all UC campuses and medical facilities, will continue until 11:59 p.m. on Thursday.

From Los Angeles Times

Rife is best known for his quick-witted crowd work, which earned him TikTok virality in 2022.

From Los Angeles Times

Related Words

• that
• whatever

Which Vs. That

What’s the difference between which and that?

Which and that are used in very similar ways (especially to introduce clauses that refer back to an earlier part), but there is often a key difference.

Before we get into the grammar, let’s take a look at two similar sentences, one using that and one using which.

I wrote about my favorite movie that was released in 1994. 

I wrote about my favorite movie, which was released in 1994. 

Both sentences are about a movie. But there’s a difference in what’s being communicated.

In the first sentence (the one using that), the speaker is indicating that the movie they wrote about is their favorite movie released in 1994—not necessarily their favorite movie in general.

In the second sentence (the one using which), the speaker is saying that the movie is their favorite in general, while also mentioning that it was released in 1994. In this sentence, you could take away the part that starts with which and the sentence would retain the same basic meaning.

But that’s not true of the first sentence—taking away that was released in 1994 would alter the meaning of the sentence.

That’s because that was released in 1994 is what’s called a restrictive clause, which is a part of a sentence that provides essential information about the part before it. A restrictive clause can’t be removed without changing the essential meaning of the sentence.

The second sentence (the one using which), ends in a nonrestrictive clause, which provides nonessential information—information that can be removed without altering the main message of the sentence. Usually, nonrestrictive clauses are marked off by commas (or em dashes). Think of a nonrestrictive clause as an aside—additional information mentioned along the way.

This grammatical distinction between that and which is largely used in formal American English. In informal speech, it is very common to use that and which interchangeably. And sometimes the difference in what they convey is very subtle or practically nonexistent.

Still, when used in clauses like the ones in our examples, which is usually preceded by a comma, but that is not.

Want to learn more? Read the full breakdown of the difference between which and that.

Quiz yourself on which vs. that!

Should which or that be used in the following sentence?

The cat ____ I saw yesterday has come back.