Eclipse

An eclipse is an astronomical event. It is when one object in the sky moves into the shadow of another such object. When an eclipse happens within a system of stars, like the Solar System, it makes a type of syzygy. This means that three or more objects in the sky are lined up in a straight line in the same gravitational system.
The term "eclipse" is most often used to describe a "solar eclipse", when the Moon's shadow crosses the Earth's surface, or a "lunar eclipse", when the Moon moves into the shadow of Earth. No solar eclipse can last longer than 7 minutes and 58 seconds because of the speed at which the Earth and Moon move. 
When the Sun is not involved, the event is called occultation. 
Etymology.
The word comes from the ancient Greek noun ('), which is from the verb ('). This means "to cease (stop) to exist (be there)".