Which Means or Which Mean? Grammar Rules, Usage, and Examples

Quick Summary:

Use “which means” when referring to a singular noun or an entire clause/statement (e.g., “He is ill, which means no class today”). Use “which mean” only when referring back to a plural noun (e.g., “The symbols which mean ‘welcome’ are on the sign”). In English grammar, “which” is a relative pronoun that links causes to their effects or provides additional details.

Introduction: Understanding the Power of “Which”

Grammar can feel confusing when phrases sound right in speech but cause uncertainty in writing. One common expression that creates confusion for English language learners is “which means.”

You encounter “which means” constantly in daily conversations, academic papers, news articles, and business presentations. It serves as a bridge, connecting a cause, fact, or statement to its logical explanation or result.

However, writers often struggle with the mechanics behind it:

Should I say “which means” or “which mean”?
How is “which” different from “that” or “who”?
What does the formal expression “by which means” mean?

This comprehensive guide breaks down the relative pronoun “which,” subject-verb agreement rules for “means” versus “mean,” and practical synonyms to help you vary your writing style with confidence.

What Does “Which” Do in a Sentence? (Relative Pronouns Explained)

To understand how “which means” works, we first need to establish the word class of “which.” In English grammar, “which” functions as a relative pronoun.

A relative pronoun relates back to another noun in the sentence (called the antecedent). That noun can be explicitly mentioned earlier in the sentence or implied by the context.

According to the Cambridge Dictionary, relative pronouns introduce a relative clause—a clause that adds extra information to a sentence.

Sentence Extension via Relative Clause:

  Base Sentence:     "There is the school..."
  Relative Clause:   "...WHICH has 2,000 students."
  Combined Result:   "There is the school WHICH has 2,000 students."

1. Referring to Explicit Nouns vs. Entire Clauses

Look at how “which” operates differently in these two sentences:

Example A: “There’s the school which has 2,000 students.”

(Here, “which” refers specifically to the single noun “school.”)
Example B: “He is unhappy, which means we are unhappy.”

(Here, “which” does not refer to a single word; it represents the entire previous statement “He is unhappy.”)

2. “Which” vs. “That” vs. “Who”

Choosing the correct relative pronoun depends on what you are describing:

Who: Used exclusively for people (“He is the man who stole the bread”).
Which: Used for animals, objects, ideas, or whole statements (“I like cameras which come with a stand”).
That: Used for animals, objects, and people in restrictive relative clauses (“I like cameras that come with a stand”).

As noted by The Writing Center, in restrictive relative clauses (where the information is essential to define the noun), many writers prefer “that” over “which” in American English, though both are grammatically valid. However, when referring back to an entire independent clause (as in Example B above), you must use “which,” not “that.”

3. “Which” in Questions (Restricted Options vs. “What”)

When forming questions, “which” can refer to an implicit noun suggested by context.

Unlike “what” questions, which are open-ended with unlimited answers, “which” questions limit the options to a specific, restricted set:

Open Choice (“What”): “What song is best?” (Any song in the world can be the answer).
Restricted Choice (“Which”): “Which song is best: ‘Don’t Stop the Music’ or ‘Funky Town’?” (The answer is restricted to the options presented).

“Which Means” vs. “Which Mean”: Subject-Verb Agreement Rules

A common point of confusion is deciding whether to add an -s to the verb: Is it “which means” or “which mean”?

Because “which” is a pronoun, it takes its grammatical number (singular or plural) from the noun or statement it represents. The conjugation of the verb that follows must agree with that reference point.

Subject-Verb Agreement Blueprint:

  [ Plural Noun ]    + WHICH  --->  MEAN   (No -s)
  [ Singular Noun ]  + WHICH  --->  MEANS  (Add -s)
  [ Whole Clause ]   + WHICH  --->  MEANS  (Default Singular)

Rule 1: Use “Which Means” for Singular Nouns

When “which” represents a single person, place, object, or concept, use the 3rd-person singular verb means:

“A loud bark, which means the dog is getting hungry, makes the house shake.”

(The singular noun “bark” dictates the singular verb “means.”)

Rule 2: Use “Which Means” for Entire Clauses

When “which” represents a full clause or situation, the verb defaults to the 3rd-person singular means:

“There is so much rain, which means that the group of kids should come inside.”

(The entire clause “There is so much rain” is treated as a single situation, requiring “means.”)

Rule 3: Use “Which Mean” for Plural Nouns

When “which” represents a plural noun phrase, drop the “-s” and use the 3rd-person plural verb mean:

“The symbols which mean ‘welcome’ are written on the entrance sign.”

(The plural noun “symbols” dictates the plural verb “mean.”)

What Does “By Which Means” Mean?

You may occasionally encounter the three-word phrase “by which means.”

This expression looks similar to “which means,” but it functions differently. In “by which means,” the word “means” is not a verb—it is a plural noun meaning methods, resources, or ways of achieving a goal.

“I don’t have the means to live independently.” (Means = financial resources)
“In the coming days, the government decided by which means they would tackle this problem.” (By which means = by which specific methods)

Using “by which means” implies that a specific, limited set of methods has been chosen, whereas “by what means” leaves the methods open to any possibility.

6 Useful Synonyms for “Which Means That”

Using “which means that” repeatedly in an essay or report can make your writing feel repetitive. You can improve your style by substituting these 6 context-specific synonyms:

Which is why (Best for casual / everyday context):

“I found clearer answers in the dictionary, which is why I used it instead of searching online.”
In such a way that (Best for describing processes):

“He organized his desk in such a way that he could quickly find important documents.”
In order that / So that (Best for formal purpose):

“I packed your bags in order that you can leave before traffic begins.”
With the result that (Best for showing outcomes):

“The audit was conducted with the result that five major security errors were discovered.”
As a result of which (Best for formal cause-and-effect):

“Several windows were damaged during the storm, as a result of which repairs were ordered.”
Whereby (Best for formal details / “by which”):

“The company established a system whereby employees can work remotely twice a week.”

Summary Comparison Table

Expression	Grammatical Function	Agreement Rule	Example Sentence
Which means	Relative pronoun + Singular verb	Modifies singular nouns or entire clauses	“The teacher is ill, which means* class is canceled.”*
Which mean	Relative pronoun + Plural verb	Modifies plural nouns	“The signs which mean* ‘stop’ are painted red.”*
By which means	Preposition + Pronoun + Noun	“Means” acts as a noun (methods/resources)	“They agreed upon by which means* to fund the project.”*
Which is why	Informal transition phrase	Replaces “which means that” in speech	“It was raining, which is why* we stayed home.”*

Practice Exercise: Test Your Knowledge

Choose the correct option to complete each sentence:

The company introduced new safety rules, ________ fewer workplace accidents.

a) which mean

b) which means

c) by what means
The Ancient Egyptian hieroglyphs, ________ “life and health,” were carved into the stone.

a) which mean

b) which means

c) whereby
Which pronoun is required when referring exclusively to a person?

a) Which

b) Who

c) That

(Answers: 1 = b, 2 = a, 3 = b)

Frequently Asked Questions

Is “which means” formal or informal?

“Which means” is grammatically neutral. It is widely accepted in both casual speech and formal writing. In highly academic papers, you can alternate it with formal transitions like “thereby,” “as a result of which,” or “consequently.”

Can you start a sentence with “Which means”?

In formal writing, starting a sentence with “Which means…” creates a sentence fragment because relative clauses are dependent clauses. However, in casual dialogue or creative writing, writers sometimes use it for stylistic emphasis (e.g., “He missed the last train. Which means he’s stuck here.”).

Is the “that” in “which means that” optional?

Yes. In the phrase “which means that there is no class,” the word “that” is a conjunction introducing an object clause and can be safely omitted (e.g., “which means there is no class”). Omitting “that” often improves sentence flow and avoids awkward phrasing like “means that that…”

Master English Grammar and Relative Clauses

Understanding how relative pronouns like “which” operate helps you build complex, fluid sentences that clearly convey cause and effect.

To continue expanding your knowledge of prepositions, relative clauses, and sentence structure, explore our complete library of educational guides on the English Forward Grammar Hub.

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