lunar:  Anything having to do with the Moon can be described as lunar.  For example, the surface of the Moon is the lunar surface.  The Latin word for moon is "luna."

lunar eclipse:  When Earth passes directly between the Sun and the Full Moon, it blocks the Sun.  This is called a lunar eclipse.  Earth casts a shadow over the Moon.  When the Moon falls completely within Earth's umbra it is called a total lunar eclipse.  Then, Earth completely blocks the Sun from the Moon.  A partial lunar eclipse occurs when only part of the Moon falls within Earth's umbra.  All or most of the night side of Earth can see a lunar eclipse.