Pronunciation

/rɪˈædiəs/

Definitions

Noun

1. Radius (n): In geometry, a straight line segment from the center of a circle to its circumference; it determines the size of the circle. Example: “The radius of the Earth is about 6,371 kilometers.”
2. (Physics) The distance from the center of a rotating body to a point on its edge, measured along a line perpendicular to the axis of rotation. Example: “A bicycle wheel has a small radius, making it easier to turn.”

Verb

• Not commonly used as a verb, but it can be extended metaphorically to mean “extend or refer to the radius of something.” Example: “The satellite’s orbit was designed to have a large radius around the planet.”

Phrases

• “The radius of a circle” refers to the measurement from the center to the edge.
• “Circular radius” is a specific term for the radius of a circle.
• “Increasing/decreasing radius” describes a change in the size of a circular object.

Example Sentences

• Noun: “The radius of the atom determines its chemical reactivity.”
• Metaphorical Verb: “The new shopping mall extends its radius to cover a larger area.”

Synonyms

• Diameter (when referring to the full length through the center)
• Circumference (the total length around the circle)
• Span
• Extent

Antonyms

• None, as radius is not a comparative term (it is a single measurement). However, if referring to a smaller circle within a larger one, the smaller circle would have a lesser radius.