radius

Language: en

🇬🇧 /ˈreɪdɪəs/ 🇺🇸 /ˈreɪdiːəs/

📖 Definitions

  1. noun
    A straight line segment from the center of a circle or sphere to its circumference or surface, or the length of such a segment.; An area or range measured outward from a central point; a circular area defined by a given distance from a center.; The shorter and thicker of the two bones in the forearm, located on the thumb side.; A movable arm of a spider's web extending from the center outward.

🔗 Details

Word forms

countable Plural: radii, radiuses

Collocations

within a radius ofradius of a circleturning radiusblast radiussearch radiusorbital radius

Derivatives

radialradiateradiationradioradially

Synonyms

rangereachspanextentscope

Commonly confused

radium
EN: 'Radium' is a radioactive chemical element; 'radius' is a geometric measurement or forearm bone.
radii
EN: 'Radii' is simply the Latin plural of 'radius', not a separate word.

Spelling tips

EN: The plural has two accepted forms: 'radii' (Latin, more common in mathematics) and 'radiuses' (English). Do not write 'radiuses' as 'radiuses'.

💬 Examples

  1. The radius of the circle is five centimeters.

  2. There are no hospitals within a ten-mile radius of the village.

  3. He fractured his radius when he fell off his bicycle.

  4. The spider sat at the center where all the radii of the web converged.