Radius
/ˈreɪ.di.əs/noun
A straight line from the center to the circumference of a circle or sphere.
Did you know?In ancient geometry, the radius symbolized balance and harmony, believed to be the key to unlocking nature's secrets.
Etymological Timeline
Latin
Latin
radius
“A spoke of a wheel or a ray of light.”
Middle Ages
Medieval Latin
radius
“Used in geometry to denote the line from the center to the perimeter.”
15th Century
English
radius
“Adopted into English as a mathematical term.”
Modern English
English
radius
“Defined in contemporary mathematics and science as the distance from the center of a circle to its edge.”