Is arctic circle a great circle?

No, the Arctic Circle is not a great circle. A great circle is a circle on the surface of a sphere that divides the sphere into two equal halves. The Arctic Circle is a circle of latitude that is located at 66°33′44″ (or 66.5622°) north of the Equator. It marks the northernmost point at which the Sun can be seen at midnight on the summer solstice. The Arctic Circle is not a great circle because it does not divide the Earth into two equal halves.