Meridian lines are halves of imaginary circles joining two diametrically opposite points on a sphere. For the earth the points are the geographical North and South poles.
Parallel lines (parallels of latitudes) are a set of imaginary lines that are parallel to the equator - which is the line of points that are equidistant from the poles.
These two sets of lines act as a set of coordinates for the surface of the earth.
Vertical lines parallel to the prime meridian are lines of longitude.
Meridian
All 'lines' of latitude are parallel to all others.No meridian of longitude is parallel to any others.-- All 'lines' of latitude are parallel to all others.-- No meridian of longitude is parallel to any other one.
The only lines that can run parallel to the Prime Meridian on any map are other meridians of longitude, and the only map on which they can be printed parallel to it is a Mercator Projection. They are not really parallel to the Prime Meridian.
Every meridian of longitude is perpendicular to every parallel of latitude, and every parallel of latitude is perpendicular to every meridian of longitude.
There are no geographic lines that are parallel to the Prime Meridian. Technically, every meridian of longitude is parallel to every other meridian of longitude, but only over an infinitesimal distance north or south of the equator. I'm quite sure that's not what you're looking for.
The lines are parallel on the map are called Latitudes.
Meridians are not parallel. Apart from that, what is the question?
No lines are parallel to the Prime Meridian. All of the meridians of longitude are farthest apart at the equator, and all converge at the north and south poles. Parallel lines would be the same distance apart everywhere, and never meet.
Lines of longitude.
Lines of longitude.
Latitude lines run east-west, parallel to the equator, while meridian lines run north-south, converging at the poles.