Wikipedia:Manual of Style/Spelling

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English spelling comparison chart

This table gives the generally preferred spellings (following government guidelines and major dictionaries). It is by no means exhaustive, but rather an overview. In some cases both variants are commonly used. The spelling listed first is the one more widely used. The suffix -ize is used in every English-speaking country. In the Commonwealth, with the exception of Canada, -ise is the preferred variant.

Australia	New Zealand	Canada	UK & Ireland	United States	Commonwealth Template:Fn
organisation	organisation	organization	organisation, organization	organization	organisation, organization
judgement, judgment	judgment, judgement	judgment, judgement	judgement, judgment	judgment, judgement	judgement, judgment
colour	colour	colour	colour	color	colour
analyse	analyse	analyze, analyse	analyse	analyze	analyse
labour (except in Labor Party)	labour	labour	labour	labor	labour
centre	centre	centre	centre	center	centre
computer program, training program(me)	computer program, training programme	computer program, training program; programme rarely used	computer program, training programme	computer program, training program	computer program, training programme
defence	defence	defence	defence	defense	defence
theatre	theatre	theatre	theatre	theater, theatre	theatre
licence (n.), license (v.)	licence (n.), license (v.)	licence (n.), license (v.)	licence (n.), license (v.)	license (n. & v.)	licence (n.), license (v.)
grey	grey	grey, gray	grey	gray, grey	grey
practice (n.), practise (v.)	practice (n.), practise (v.)	practice (n.), practise (v.)	practice (n.), practise (v.)	practice (n. & v.)	practice (n.), practise (v.)
aluminium	aluminium	aluminum, aluminium	aluminium	aluminum	aluminium
dialogue	dialogue	dialogue	dialogue	dialogue, dialog	dialogue
fulfil	fulfil	fulfill, fulfil	fulfil	fulfill	fulfil
travelling	travelling	travelling	travelling	traveling	travelling
fjord	fiord	fjord	fjord	fjord	fjord
kerb	kerb	curb	kerb	curb	kerb
tyre	tyre	tire	tyre	tire	tyre

Template:Fnb General Commonwealth spelling, for example in South Africa and Singapore. Canadian spelling is an exception.

Different spellings - different meanings

There are several words that change their meaning when spelled differently.

programme - program: In Commonwealth English, the spelling program is used for computer program. In all other cases programme is used.

theatre - theater: In American English, theatre is commonly used among theatre professionals. Theatre tends to refer to the art, theater to the building. The spelling theatre is also used in names like Kodak Theatre and AMC Theatres

disc - disk: In Commonwealth English, the usual spelling is disc (meaning: thin flat circular object), but in computing disk is usually used, as in Hard disk, when referring to magnetic disks. In case of optical discs, such as "compact disc", the other spelling is used.

Judgement - Judgment: In Australian Law a Judge's decision in a case is always spelt Judgment. On the other hand, the forming of opinion or conclusion by an ordinary person, is usually spelt judgement.

Inquiry - Enquiry: In Commonwealth English, an enquiry is a request for information, but an inquiry is a formal investigation.

International organizations

There are three major English spelling standards used by international organizations and publishers:

British English with -ize (Oxford spelling)

Spellings: centre, programme, labour, defence, organization, recognize, but: analyse
Language tag (a code identifying the language used): en-GB-oed, this standard is based on the Oxford English Dictionary.

Examples of organizations adhering to this standard: United Nations Organization (UN, WHO, UNESCO, UNICEF, etc.), World Trade Organization (WTO), International Organization for Standardization (ISO), International Electrotechnical Commission (IEC), International Telecommunication Union (ITU), International Labour Organization (ILO), International Atomic Energy Agency (IAEA), Organization of the Petroleum Exporting Countries (OPEC), South Asian Association for Regional Cooperation (SAARC), International Criminal Police Organization (Interpol), International Committee of the Red Cross (ICRC), World Wildlife Federation (WWF), Amnesty International, World Economic Forum

Major Publications: Nature, Times Literary Supplement, Encyclopaedia Britannica

British English with -ise

Spellings: centre, programme, labour, defence, organisation, recognise, analyse
Language tag en-GB, this standard is used and recommended by the UK government.

Examples of organizations adhering to this standard: North Atlantic Treaty Organisation (NATO), European Union (EU), Organisation of Economic Co-operation and Development (OECD), Commonwealth Secretariat (Commonwealth of Nations), African Union (AU), Organisation of Eastern Caribbean States (OECS), International Olympic Committee (IOC), Fédération Internationale de Football Association (FIFA), Transparency International, Greenpeace.

Major publications: The Economist, The Times, Financial Times, New Scientist, The Lancet

American English

Spellings: center, program, labor, defense, organization, recognize, analyze
Language tag en-US, this standard is used by the U.S. government.

Examples of organizations adhering to this standard: International Monetary Fund (IMF), World Bank, Organization of American States (OAS), NAFTA Secretariat.

Major publications: International Herald Tribune, New York Times, Wall Street Journal, Time Magazine, Newsweek, Science, Scientific American

Preferred variants

In British and American English, many words have variant spellings, but most of the time one variant is preferred over the other. In dictionaries, the preferred spelling is listed first among the headwords of an entry. Examples follow:

acknowledgement vs acknowledgment: acknowledgement is preferred in British English, acknowledgment in American English.
judgement vs judgment: judgement is preferred in British English, judgment in American English.
per cent vs percent: per cent is preferred in British English, percent in American English.
dialogue vs dialog: In a non-technical context, the spelling dialogue is preferred in American English. In Webster's dictionary, dialogue is given first.
catalogue vs catalog: Interestingly, Webster's treats this case differently — catalog is the preferred spelling in American English.
glamour vs glamor: The spelling glamour is preferred in both American and British English
neuron vs neurone: Neuron is the preferred spelling in both British and American English
foetus vs fetus: In American English, foetus is usually not used. In British English usage is divided. In academic literature, fetus is preferred, in newspapers and general non-scientific use foetus.

Archaic variants:

gaol: the usual modern spelling is jail
gramme: the usual modern spelling is gram
masque: modern spelling is mask
connexion: this word is usually spelt connection.