the great circle representing the apparent annual path of the sun; the plane of the Earth's orbit around the sun; makes an angle of about 23 degrees with the equator; "all of the planets rotate the sun in approximately the same ecliptic"
an imaginary line around the Earth forming the great circle that is equidistant from the north and south poles; "the equator is the boundary between the northern and southern hemispheres"
a circle dividing a sphere or other surface into two usually equal and symmetrical parts
an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator; "all points on the same meridian have the same longitude"