Explain the difference between parallel and meridian.

Parallels : The north or south angular distance of a place from the equator is called latitude. Lines drawn east-west parallel to the equator are called latitudes. There are 90° latitude north of equator and 90° latitude south of the equator. These distance of 90° latitude is points only called north pole and south pole.
The links joining north pole and south pole are called meridians of longitude. The meridian passing through Greenwich is known as Prime Meridian. There are 180 meridians towards the east and west of the prime meridian. Thus, there are 360 meridians in all.