Radius Meaning and Definition

Pronunciation

/ˈreɪdiəs/ 🔊

Part of Speech

Noun

Definition

The distance from the center of a circle or sphere to its circumference or the edge of a semicircle, or the spatial region bounded by such a circumference or edge.

Examples

• The architect designed a building with a circular radius to maximize natural light.
• In physics, the concept of radius is crucial in understanding the properties of spheres and circles.

Synonyms

• Diameter
• Radius-vector

Antonyms

• Circumference
• Polyhedron

Etymology

The word “radius” comes from the Latin “radius,” meaning “spoke” or “ray,” which is derived from the Greek “راهος” (rachis), meaning “backbone” or “spine.”

Usage Notes

The term “radius” is often used in mathematics and physics to describe the distance from the center of a circle or sphere to its circumference. However, in everyday language, it can also refer to the spatial region bounded by such a circumference or edge.

Idiomatic Expressions or Phrases

• “Radius of action” refers to the maximum range of an object’s ability to influence its surroundings.
• “Radius of influence” is used in physics to describe the region affected by a force.

Related Words or Phrases

• Circle
• Sphere
• Polygon

Collocations

• Radius of a circle
• Radius of a sphere
• Radius of curvature

Frequency of Use

The word “radius” is relatively common in scientific and mathematical contexts, but less commonly used in everyday language.

Common Misspellings

• Raddius
• Radius