半径

半径 (bàn jìng) refers to the distance from the center of a circle or sphere to its edge. It is a fundamental concept in geometry, distinguishing it from diameter, which is twice the radius.

The character 半 (bàn) means 'half,' and 径 (jìng) originally meant 'path' or 'road,' but in this context, it refers to a straight line from the center. Together, they form a term that literally means 'half path,' symbolizing the half-length of a diameter.

Half-radius is commonly used in mathematics, engineering, and everyday measurements. In Chinese culture, understanding geometric terms like 半径 is essential for fields such as architecture, design, and technology. It is also often taught in primary school math classes.