Meridian is a term that comes from the latin meridiānus and which designates what is relative or owned by midday. By extension, the term is used as an adjective to describe something very clear and bright.
Meridians, moreover, are the great circles of the celestial sphere passing through the poles. We can say that the meridians are imaginary lines that are used to define the schedule (or schedules).
The base Meridian from which longitudes are measured is the Greenwich Meridian. This imaginary circumference connects the poles by the old Observatory in the English town of Greenwich had been adopted as a reference in 1884.
From North to South, the Greenwich Meridian runs through the United Kingdom, the France, the Spain, the Algeria, Mali, Burkina Faso, Togo and Ghana.
The Meridian that passes through the point where the observer is called the local Meridian. This Meridian can be divided into two semi-circles on the axis of rotation of the Earth, namely: the upper Meridian (PM) and the lower Meridian (AM).
The solar time is the measurement of time that is based on the apparent motion of the sun above the horizon. When the Sun passes through the Meridian, it reached its highest in the sky and it is at this time that it is midday.
In a quite different context, Le Meridien is the name of a group of hotels and luxury of French origin, which has more than 120 hotels worldwide.