In the online version of Cambridge Dictionary, there are these definitions for the next two words:

Behaviour = the way that someone behaves

Behavior = a particular way of acting

What would be a difference between behavior and behaviour by some example?

  • 1
    Related pages comparing the two: Grammarist, Grammar.com, Writing Explained and Wikipedia (which only briefly notes both versions). I found these by Googling "behavior and behaviour".
    – NotThatGuy
    Commented Mar 27, 2019 at 16:18
  • 3
    If you look at the 2 definitions, you will see that they come from different sources; this is why the definitions differ in their wording.
    – Dancrumb
    Commented Mar 28, 2019 at 20:11
  • I am not sure as I am not up to date with rules being followed here, but this seems like a very basic question to start with and should not be allowed in this forum. And if it has to be, it sets a bad example for more such questions to be asked in future.
    – Mohit
    Commented Apr 18, 2019 at 12:20

4 Answers 4


They mean the same thing; behaviour is the British English spelling; behavior is the American spelling. The definitions say the same thing in different ways.

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    It should be noted that this is very common - there are many words which end in "our" in British English and "or" in American English. Commented Mar 27, 2019 at 12:49
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    Right, Darrel, and I'd like to add that the words ‘motor’, ‘rotor’, ‘abhor’ are not among them. :) Commented Mar 28, 2019 at 20:48
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    @ArtyomLugovoy you are coming at it from the other way. Look first for the 'our' words in BE then their corresponding word in AmE.
    – mcalex
    Commented Mar 29, 2019 at 7:50
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    @mcalex I just mentioned that if one sees an 'or' word, that doesn't necessarily mean there is a corresponding 'our' word. As well as the words ‘pour’ and ‘sour’ existing in BrE are the same in AmE. Commented Mar 29, 2019 at 10:34

In fact, there is no difference between behaviour and behavior except spelling. The former is preferred in British and Commonwealth English, the latter is the American spelling.

The entries are confusing because there is no single "Cambridge Dictionary." Cambridge University Press actually publishes dozens of different dictionaries. Their website, however, searches them all at once, and returns definitions which may or may not be relevant to you.

When you look up behaviour, you are given entries from the Cambridge Advanced Learner's Dictionary & Thesaurus and the Cambridge Business English Dictionary. When you look up behavior, you are given the entry in the Cambridge Academic Content Dictionary, and from the Cambridge Business English Dictionary a pointer to the entry for behaviour. Because the target audience for each dictionary is different, you see slightly different entries, but this is a quirk of the Cambridge Academic Content Dictionary failing to synonymize the spellings.

I commend you for doing your best with references, but would also recommend you limit searches to a learner's dictionary (e.g. Collins, Oxford, Macmillan, Cambridge, or Merriam-Webster) to avoid this happening in the future.

  • your Cambridge there is no IPA for US and because I stay with my Cambridge. Thank a lot for your excellent explanation to me.
    – b2ok
    Commented Mar 26, 2019 at 21:47
  • All the learner's dictionaries listed above, except Macmillan, give IPA pronunciations for both US and UK. The Cambridge Learner's shows both pronunciations if they are different, but only shows only a single one if they are the same.
    – AndyB
    Commented Mar 28, 2019 at 20:00

In short, they're the same word spelt differently in the US and the UK.

It's not very obvious because of the way Cambridge has laid out their pages.


noun UK US behavior


noun [ C/U ] CDN BR behaviour


noun [ U ]

→ behaviour

Wiktionary's entries are much clearer:


Alternative forms

behavior (US)


Alternative forms

behaviour (UK)


Behaviour is the British spelling and behavior is the American variant.

The British spelling is in this case slightly more faithful to the etymology of the word.

The OED has the following etymology of behaviour:

  • formed on the verb behave, by form-analogy with havour, havyoure, common 15–16th century forms of the word which was originally the noun aver (q.v.), aveyr, also in 15th century avoir; really Old French aveir, avoir, in sense of ‘having, possession,’ but naturally affiliated in English to the native verb have, and spelt haver, havour, haviour, etc. Hence, by analogy, have: havour, -iour: behave: behavour, -iour.
  • The formation might be confirmed by the (apparently) parallel demeanour, from demean (oneself). For the -iour see havour.

The etymology of havour:

  • Originally an adoption of the French aveir, avoir ‘having, possession, property, estate, wealth, etc.’, substantive use of avoir, Old French aveir ‘to have’.
  • First used in English in the Norman form aveyr [...]; the Central French form avoir appeared about 1400, and displaced aver, except in the northern dialect, where that form survived in a specific sense.
  • In 14–15th century, association with the English have, having, introduced the variants haver, havoir, havour, and the h was established before 1500. At the same time the parallel behavour was formed on the English behave; and in 16th century havour, beside its original sense of ‘possession’, took also that of behavour.
  • Subsequently the termination of both words passed through -eour to -iour (cf. saviour, and vulgar ‘lovier’); the original sense ‘possession’ became obsolete; and, in the new sense, haviour came down alongside of behaviour, of which it may often have been viewed as a shortened by-form.

The American spelling, behavior, on the other hand, is effectively more 'phonetic' in nature, in that it dispenses with the u (there are only a few exceptions), which is otherwise not pronounced. At the beginning of the 19th century, Noah Webster pushed this change primarily via his dictionary, and Americans gradually adopted the new spelling. Etymonline.com says:

When the Americans began to consistently spell it one way, however, the British reflexively hardened their insistence on the other. "The American abolition of -our in such words as honour and favour has probably retarded rather than quickened English progress in the same direction." [Fowler]

If you're using American English, you should write behavior. If, on the other hand, you're using the British variant, write behaviour. The important thing is to be be consistent, as the commenters say: it'd be considered unusual to have both colour and behavior in the same sentence.

In short: pick a dialect and use it consistently.

  • 4
    This is very much not correct. I don't really know where to start, but there is literally no sense in which British English is 'more correct' than any other form of English. Likewise, many American words and phrases are older than the British English equivalents, and were preserved by the separation of North American and British populations. Furthermore, 'color' et al were common spellings before the standardization of spelling in Britain, and '-ize' has only recently become something Britons generally avoid. '-ize' and '-ise' are still both acceptable in British English.
    – fred2
    Commented Mar 28, 2019 at 18:57
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    It is far more important that someone be consistent in their choice of English variation than to choose one particular one over the other. If I see “colour” I expect that the grammar and vocabulary will be British. If the subsequent text uses American grammar or vocabulary, then I will view it as a mistake, where I wouldn’t if the “color” spelling were used. Students should learn whichever variation they have the best access to native speakers of.
    – ColleenV
    Commented Mar 28, 2019 at 20:56
  • @fred2 Apologies, I didn't mean to stir sentiment. I'm not implying 'British' English is somehow more noble. It's simply a matter of definition. 'English' is the language of England. Not to mention, within England there's a lot of regional dialects too, so the canonical version of English is that known as 'The Queen's tongue', which is what most people mean by 'British' English. Older origins are not relevant. I'm from Cyprus, which is closer to ancient Greek than modern Greek. But I would never claim the Cypriot dialect is canonical for that reason. Greek is the language spoken in Greece. Commented Mar 28, 2019 at 20:58
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    @TasosPapastylianou This answer, along with the corresponding comments, shows a profound ignorance of how the English language developed, and what a language is. In linguistics (a field you evidently have no experience in) there's a distinction between British English (BrE) and American English (AmE) as two families of dialects which implement what linguists call Standard English. Not all dialects implement Standard English, but those that we call BrE and AmE do.
    – user3395
    Commented Mar 29, 2019 at 15:09
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    @TasosPapastylianou "In any case, the canonical 'British' spelling [...] is typically the more 'correct' one in a linguistic sense" – this is absolutely incorrect. Do you understand that? You're suggesting that BrE be used as some sort of canonical English, and you base that suggestion on false claims such as the above.
    – user3395
    Commented Mar 29, 2019 at 16:57

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