Past tense and past participle of emphasise (British spelling), meaning to give special attention or prominence to something.
From emphasis + -ise (British spelling) + -ed (past tense marker). The -ise ending is standard in British English, while American English uses -ize.
This spelling difference between British 'emphasised' and American 'emphasized' stems from the Great Spelling Reform that never quite happened—two countries kept their own preferences.
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