What is the circle of illumination.? How is it different from earths axis?

What is the circle of illumination.?
How is it different from earths axis?

Circle of illumination is an imaginary line that separates light from darkness and day from night.

Earth’s axis refers to an imaginary line going through the center of the earth from top to bottom.

Thus, while circle of illumination separates light from darkness and day from night, axis is a line along which the earth’s rotates.