What is the difference between circumference and perimeter?

The main difference between circumference and perimeter lies in the shapes they describe:

• Perimeter: The perimeter is the total distance around the outside of any two-dimensional shape. This shape can be a polygon (like a square, rectangle, triangle), or any irregular shape with straight or curved sides. You find the perimeter by adding up the lengths of all the sides.

• Circumference: The circumference is the specific term used to describe the distance around the outside of a circle (or an ellipse, though that's less common). It is essentially the perimeter of a circle. Because circles don't have sides, we use a special formula to calculate the circumference: C = 2πr, where r is the radius of the circle and π (pi) is a mathematical constant approximately equal to 3.14159.

In short, circumference is a specific type of perimeter that applies only to circles. Perimeter is a more general term that can be used for any closed two-dimensional shape.