Question

explain why lines of longitude are called meridians of longitude

Answer 1

All meridians meet at North and South Poles. Longitude is related to latitude, the measurement of distance North or South of Equator.

Answer 2

Answer:

Longitudes are known as meridians because in Geographical sense, meridians are great circles which are not parallel to each other but intersect each other at the North and the South Poles. Same stands true of the longitudes. All longitudes are great circles which meet at the Poles.