What imaganary line separates one line from the next on earth?

The imaginary line that separates one line of latitude from the next on Earth is called a parallel. Parallels run east-west and measure degrees north or south of the Equator, which is at 0 degrees latitude. Conversely, lines of longitude, known as meridians, run north-south and measure degrees east or west of the Prime Meridian, which is at 0 degrees longitude. Together, these lines create a grid system for locating points on the Earth's surface.