The lines of longitude are called meridians of longitude because they run from the North Pole to the South Pole and converge at the poles. These lines are used to measure the angular distance east or west of the Prime Meridian, which is located in Greenwich, England. The Prime Meridian has a longitude of 0 degrees, and the meridians to the east and west of it are numbered in degrees up to 180 degrees.

The lines of latitude are called parallels of latitude because they run parallel to the equator, which is the line of 0 degrees latitude. These lines are used to measure the angular distance north or south of the equator. The equator is the starting point for measuring latitude, and the lines to the north and south of it are numbered in degrees up to 90 degrees.
By understanding the differences between meridians of longitude and parallels of latitude, we can accurately locate any point on the Earth's surface using a system of coordinates. This system helps us navigate, create maps, and understand global relationships.