To make something alkaline or to treat something with an alkali (British spelling).
From alkali (Arabic origin, meaning plant ashes) + '-ise' (British) or '-ize' (American). The verb form was created when chemists needed a way to express the action of adding or creating alkalinity.
Most English speakers don't know that 'alkali' is actually an Arabic word (al-qali) meaning plant ashes—it came to European chemistry through medieval traders and Middle Eastern scholars, making it a beautiful example of scientific vocabulary's multicultural roots.
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