How to Pronounce “radius”

American (US)

/ˈɹeɪ.di.əs/

British (UK)

/ˈɹeɪ.di.əs/

noun — The long bone in the forearm, on the side of the thumb.

Where the stress falls. “radius” has 3 syllables, and the transcription /ˈɹeɪ.di.əs/ puts the primary stress mark (ˈ) before the first one — so the first syllable is the longest and loudest. The others are said quickly and lightly.

An unstressed vowel reduces to schwa. /ˈɹeɪ.di.əs/ contains a schwa /ə/ — the short, neutral “uh” that English unstressed syllables collapse into. Saying /ə/ there, instead of the vowel the spelling suggests, is most of what makes the word sound native.

What does "radius" mean?

radius (noun): The long bone in the forearm, on the side of the thumb.

How do you pronounce "radius" in American vs British English?

Both accents use the same sequence of phonemes for "radius", /ˈɹeɪ.di.əs/, so the difference you hear is in how the vowels are coloured rather than in which sounds are used. Play both on this page to compare.

What is the IPA transcription of "radius"?

/ˈɹeɪ.di.əs/ in American English, /ˈɹeɪ.di.əs/ in British English.

Which syllable is stressed in "radius"?

“radius” has 3 syllables, and the transcription /ˈɹeɪ.di.əs/ puts the primary stress mark (ˈ) before the first one — so the first syllable is the longest and loudest. The others are said quickly and lightly.