ise or ize?

09 Apr

Having a Bank Holiday is no excuse for avoiding the big questions: so here we go with -ise and -ize. We’re talking here about whether you use organisation or organization; analyse or analyze.

Now, people assume that -ise is British and -ize is American, but that isn’t exactly the case. And – of course – it isn’t that simple, either. The one thing that is vitally important, however, is being consistent within a document or documentation.

In British English, either -ise or -ize is acceptable (most people don’t seem to know that. Oxford University Press, for example, use -ize in their house style. If you’re writing articles for journals, it’s important to check for house style on this). In American English, however, it’s -ize all the way. Well, nearly all the way.

Ise is obligatory in some words, and I have to thank New Hart’s Rules for putting this all in one place as an easy reference. So, -ise rather than -ize is obligatory when:

  • it forms part of a larger word element, such as -cise (cutting: excise), -vise (seeing: supervise), -mise (sending), or -prise (taking) [if you can think of any examples of the last two with that meaning, please let me know – I presume they are words coming from the French roots mener and prener but apart from that I’m stumped for examples that include the meaning sending or taking]
  • it corresponds to a noun that has an s in the stem: advertisement – advertise; television – televise

Common words that must use -ise in American and British English:

advertise, advise, apprise, arise, chastise, circumcise, comprise, compromise, demise, despise, devise, (dis)enfranchise, disguise, enterprise, excise, exercise, improvise, incise, merchandise, premise, prise (open), revise, supervise, surmise, surprise, televise

When we move on to the -yse / -yze debate, it’s much more simple: -yse in British English, -yze in American, so analyse vs. analyze, etc.

This issue comes up a lot for me, because I work with many students who, although studying in the UK, have American English as their standard language in Word and use American spellings throughout. Except when they don’t. If they mix them up, as they invariably do, well, I used to ask which they preferred but now I just pick the most common version they use and tell them that I’ve done that.

But the most important things are to

  1. Obey house style, if there is one (particularly important if you’re writing journal articles)
  2. Be consistent.
  3. If you are quoting from a source which uses a different spelling from your required one (e.g. you are working with -ise and it uses -ize), leave the word in the original form in which it was printed in a direct quotation. See more in my posts on quoting sources [coming soon].

You can find more troublesome pairs here and the index to them all so far is here.


Tags: , , ,

13 responses to “ise or ize?

  1. Vanessa Chapman

    April 9, 2012 at 11:45 am

    Thank you, I’ve learned something! I did assume that it is always the case for ‘ise’ to be British and ‘ize’ to be American.

    I have another troublesome pair suggestion for you too – illusion or delusion.


    • Liz at Libro

      April 9, 2012 at 12:53 pm

      Ah – that’s a good one, thanks. And most people don’t realise, especially that some UK house styles actually prefer -ize.


      • Gill Rose

        April 9, 2012 at 5:59 pm

        Why would they? Why??


  2. Liz at Libro

    April 9, 2012 at 6:05 pm

    Well, if you insist on knowing, here is what Oxford say: “[-ize endings] were favoured on both phonetic and etymological grounds: -ize corresponds more closely to the Greek root of most -ize verbs, -izo”.


    • Rose Harris

      April 10, 2012 at 10:13 am

      Didn’t know that. My interesting new fact of the day!


      • Liz at Libro

        April 10, 2012 at 1:54 pm

        Excellent – I like to provide people with interesting new facts!


  3. ianbraisby

    April 9, 2012 at 6:52 pm

    Also, often better to use the -ize in anything designed for an “international” audience, due to the global dominance of what are seen as “American” conventions. Especially any documentation relating to the Internet, software etc. as most standard computer packages are either developed in the US or have their first English version localised (or localized?) there.


    • Liz at Libro

      April 9, 2012 at 6:54 pm

      Indeed. Localized if they’re asking me to do it, localised when I talk about it so I look like I know what I’m talking about! Sometimes it’s an advantage to seem terrible British English but usually I go for -ized in text that is more internationally based (for other people) as it is still correct in the UK.


  4. Colin

    April 22, 2013 at 5:04 pm

    Can I suggest ‘promise’ and ‘reprise’ for the sending & taking words? Having checked my online etymology dictionary, ‘promise’ appears to come from Latin pro+mittere meaning “before + to put, send”. Makes sense, I suppose.


    • Liz at Libro

      April 22, 2013 at 5:07 pm

      Interesting … here’s the thing, I think it’s only words that sound like “eyes” that take a z at all … isn’t it? Does that make sense? I can’t think of any “iss” or “ees” words that would take a z in Oxford or American English …

      That’s interesting in itself though, as I hadn’t thought of it before!


  5. ozonenut

    September 6, 2013 at 6:34 am

    How about enterprise = undertaking?


    • Liz at Libro

      September 6, 2013 at 7:11 am

      I mention enterprise in the list of words that always use s, but not sure what you’re suggesting here (sorry!)


      • ozonenut

        September 6, 2013 at 7:16 am

        Sorry, missed that, I was responding to your request in the previous paragraph for examples of words which use -prise in the sense of to take.



I love hearing from my readers - do please leave a comment!

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: