Sorry WAV look it up in an English dictionary...

'The -ize spelling is preferred by some authoritative British sources including the Oxford English Dictionary — which, until recently, did not list the -ise form of many words, even as an alternative — and Fowler's Modern English Usage. The OED firmly deprecates usage of "-ise", stating, "[T]he suffix…, whatever the element to which it is added, is in its origin the Gr[eek] -ιζειν, L[atin] -izāre; and, as the pronunciation is also with z, there is no reason why in English the special French spelling in -iser should be followed, in opposition to that which is at once etymological and phonetic."[4'

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