Is there a plural form of "radius"?

I don't know how to say radius in plural. Is there any form for this word? Or is it just radiuses?

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Best answer

Hello Cungkhe, The word 'Radius' comes from the Latin word meaning 'spoke of a chariot wheel'. This means it doesn't follow our usual rules for making nouns plural (adding s or es). The first official and more formal plural for 'radius', because of this Latin heritage, is 'Radii'. It is pronounced the same in both British and American English = [ray-dee-eye]. I would advise using this form in FORMAL writing. The second plural for 'radius' is one that has become more popular over the years, 'Radiuses'. This is often referred to as the 'conversation English plural'. This is pronounced [ray-dee-us-iz]. I would advise using this form in your everyday English. So to sum up Cungkhe, Radii = more formal and academic English Radiuses = more informal, conversational English I hope that helps Best wishes Laura

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