1. What is 'bleach'?
  2. What does 'bleach' mean?

I want to ask about the definition of a word. Are both sentences OK?

I don't know why I sometimes think that it is not suitable to use the word 'mean' or 'meaning' for some words like some materials, or places etc.

  • Can't you tell us why you think posing a question with the verb "be" is different from posing a question with the verb "mean"? Aren't they fundamentally different as you show in your sentences?
    – Lambie
    Commented Sep 24, 2018 at 14:11
  • 4
    When you come across a new word in some real-world situation, it's often the case that the context already tells you whether that word is likely to be a noun or a verb. My feeling is that people would normally use OP's format #1 if they think it's a noun, and format #2 if it's more likely to be a verb. And that people answering the question will tend to understand and react to that implication, so it's more likely they'd answer OP's first version with It's a chemical liquid that kills toilet germs, where for the second they might say It means to make something lighter in colour. Commented Sep 24, 2018 at 15:40
  • Imagine a group of students who are asked some questions about the new words that they have already studied. Can the teacher ask 'What is a bottle? (The students have learned it as a noun) Can the teacher ask 'What does 'bottle' mean? The students' answer will be something like this ' It is a glass or plastic container for liquids, with a thin part at the top.
    – Mahdi
    Commented Sep 24, 2018 at 18:09
  • 1
    The structure "What does x mean" implies that x is a verb. Asking "What is a bottle" would definitely result in the answer you want, whereas "What does bottle mean" could reasonably be answered as "To contain a liquid or gas in a bottle" (i.e. the definition of the verb "to bottle"). When the word can only be a noun it is not ambiguous. Commented Sep 25, 2018 at 8:13

5 Answers 5


Both questions are OK but they could be slightly clearer.

If you want to know the meaning of the word, it's better to ask:

What does the word bleach mean?

This makes it clear that you are looking for the significance of the word - what it denotes.

To ask: what is ....? might bring up a more scientific answer or philosophical answer.

For example, there's a difference between asking what is life and what does the word life mean?

  • 18
    One other difference I thought of: the word bleach can be a verb or noun. If we ask, "What is bleach?" the we may get an answer only relating to the noun; however, if we ask, "What does the word bleach mean?" we may get an answer describing both the noun and the verb.
    – J.R.
    Commented Sep 24, 2018 at 14:29
  • @J.R.: You've altered the example. "The word" is what's causing that shift. You could just as well ask "What is the word "bleach"?" and get the same semantically oriented answer. The difference you're pointing out is not related to the verbs used (is/does mean).
    – Flater
    Commented Sep 25, 2018 at 6:33
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    @Flater - I followed the shift given in Ronald's answer here – what does the word 'life' mean? In any case, I think my point holds whether we ask, "What does the word bleach mean?" or if we ask, "What does 'bleach' mean?" Either question might get the answer, "To lighten by exposure to sunlight" – something I'm less likely to say if someone asks me, "What is bleach?"
    – J.R.
    Commented Sep 25, 2018 at 8:15

If you want to know what the substance itself is:

What is bleach?

If you want to know what the word means, you would emphasize the word typographically, or intonationally when speaking, to show that you're asking about the word:

What does bleach mean?

What does "bleach" mean?

What does the word "bleach" mean?


I want to ask about the definition of a word. Are both sentences OK?

As a native speaker I would consider both sentances ok, but (depending a bit on the context) I would interpret them differently.

"what is x" implies that x is a mass noun (for a countable noun it would be "what is a x"). "what does x mean" is more likely to be used with a verb. The word "bleach" can be both a mass-noun and a verb. So one might answer those questions as.

What is 'bleach'?

A chemical, most commonly sodium hyperchlorate used for disinfection and bleaching.

What does 'bleach' mean?

To whiten something, usually by the application of bleach though sometimes also by other mechanisms such as exposure to UV.

  • Thanks, If I ask a student 'what does bleach mean?' and he answers like this 'it is a chemical, most commonly sodium hypochlorite used for disinfection and bleaching.' Is it correct?
    – Mahdi
    Commented Sep 24, 2018 at 17:38
  • Yes. You might follow up by asking what is bleach used for, or what would happen if you were to spill bleach onto something.
    – CrossRoads
    Commented Sep 24, 2018 at 18:42
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    But one might also answer the second question with the first answer.
    – phoog
    Commented Sep 24, 2018 at 19:07
  • "What does x mean" will attract an adjective answer before a verb answer (e.g. 'square', 'smooth').
    – amI
    Commented Sep 24, 2018 at 22:50
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    Re: "'what does x mean' is more likely to be used with a verb": I'm not sure about that. In my experience, in everyday conversation, the verb equivalent of "What is 'bleach'?" is "What is 'bleaching'?" (using the gerund). I think "What does 'bleach' mean?" is completely open with respect to the part of speech of the word being asked about.
    – ruakh
    Commented Sep 24, 2018 at 23:39

Either sentence is fine, and the difference between them is very small.

The second sentence is very unambiguous, and it works with essentially every word in the English language (though it would be weird if you used it for one of the words already in the sentence):

What does "_____" mean?

Put any word you want for the blank and it will be a reasonable way to ask for the definition of that word. Sometimes you will not get the desired definition because some words have multiple definitions and without sufficient context someone could give you a different one than you wanted. In writing using quotation marks to indicate that you are talking about the word itself is traditional, but there isn't usually any need to do so in speech and the sentence is unlikely to be misunderstood without them in writing either.

Your first sentence also makes sense and would be interpreted almost identically, but would typically be applied to a much smaller subset of words, specifically nouns referring to a substance or inanimate object. That restriction allows the sentence to be grammatically and semantically correct without quotation marks. Bleach works: "What is bleach?" Other words also work, but can sometimes require an article, and that article could require its own comprehension. For example, if someone tells you "Hand me the wrench." a (potentially) appropriate response could be "What is a wrench?" whereas "What is the wrench?" would be unusual. In this phrasing, the concept you are asking about should fit in the sentence grammatically, which is why quotation marks aren't needed.

Part of the reason to avoid that wording unless you know that the word refers to an object or substance is that it overlaps with a different sentence with the same words but different meaning. If you use the phrase with an adjective instead, there's a good chance you will be interpreted differently. For example, the sentence "What is disgusting?" should be answered with one or more things to which the adjective "disgusting" is applicable, and would typically not be answered by a definition for "disgusting". In spoken English this would typically involve noticeable emphasis on the word "what", and you could encourage the other interpretation by emphasizing the word "disgusting" instead.

Finally, a third phrasing can sometimes sound more fluent than the others and better suits some contexts. In particular, it's recommended if somebody uses a word you do know, but the definition you know for it doesn't make sense with how they used it. For example, if you hear that someone "bleached their hair" but are only familiar with bleach as a household cleaning chemical, the best way to ask for clarification would be "What do you mean by "bleached"?" I can't give an intuitive explanation for why that phrasing works, but it is (in my experience) the best way to get an answer like "Bleaching hair is a cosmetic procedure that lightens hair color dramatically." rather than "Bleach is a household cleaning chemical." which doesn't necessarily help understand the context. It's important to only use this in a context where you are speaking to someone who also heard the same phrase you are asking about, but doesn't exclusively require you to ask the original speaker. If you are asking a friend about something that was said during a speech or lecture which just ended you could ask "What did he mean by "_____"?"



"What is bleach" directly references the substance bleach. If you ask me this, I will explain to you how bleach works and what it is used for. You're asking about the substance here.

"What does bleach mean" will lead me to explain what "to bleach" is because bleach is sometimes used as a verb. i.e. "Just bleach it." They're not the same thing. I don't think they're synonymous. Here you're asking strictly for a word definition.

If you don't mind an awkward conversation following either of these questions, then you could use them interchangeably, though you're going to sound strange doing that.

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