What is the distance around a circle called?

The distance around a circle is called the circumference. This term refers specifically to the total length of the circle's boundary or perimeter.

To understand why circumference is the correct term, think of a circle as being a closed curve where all points are equidistant from the center. The formula to calculate the circumference is often given as (C = 2\pi r) or (C = \pi d), where (r) is the radius and (d) is the diameter of the circle. The use of pi ((\pi)) is crucial here, as it represents the ratio of the circumference to the diameter, illustrating the unique relationship between these measurements.

On the other hand, area refers to the space contained within the circle, diameter measures the distance across the circle through its center, and radius measures the distance from the center of the circle to any point on its boundary. Each of these terms describes different attributes of a circle, but only circumference indicates the distance around it.