Latitude and longitude are imaginary (unreal) lines drawn on maps to easily locate places on the Earth. Latitude is distance north or south of the equator (an imaginary circle around the Earth halfway between the North Pole and the South Pole) and longitude is distance east or west of the prime meridian (an imaginary line running from north to south through Greenwich, England). Both are measured in terms of the 360 degrees (symbolized by °) of a circle.
Hope this helps!