You are referring to the Equator, which bisects the earth into the Northern and Southern Hemispheres. It is located at 0 degrees latitude.
In addition, there are innumerable lines of longitude that make complete circles around the earth, that run north and south.
The Equator.
The imaginary circle around the earth that divides it into two halves is called the Equator. It is located at 0 degrees latitude and serves as the starting point for measuring latitude.
An imaginary great circle around Earth, equidistant from the poles.
The equator runs around the center of the earth.
orbit
The equator divides the northern hemisphere from the southern hemisphere.
The equator is the best known such imaginary line. However, latitudes (including the Arctic Circle) are also imaginary lines encircling the earth as are longitudes.
equator
The celestial equator is an imaginary circle created by extending Earth's equator into space. Zenith is an imaginary point in the sky directly above and observer on earth.
The imaginary line that cuts the earth into two equal parts is called the equator. It is an imaginary circle around the Earth that is equidistant from the North and South poles. It divides the Earth into the Northern Hemisphere and the Southern Hemisphere.
All lines of Latitude circle the earth, they are imaginary devices used on maps. Latitude is horizontal, think of the Horizon.
The imaginary line that circles the Earth is called the Equator. It divides the Earth into the Northern Hemisphere and the Southern Hemisphere.