A Metor Shower is when a number of bright objects are seen up in the sky at night, streaming through our atmosphere. Sometimes meteors land on the Earth.
Meteors are pieces of rock, some very small, some very large. Many of them come from the Asteroid Belt which can be seen by telescope in an orbit further out from the Sun than the Earth.
A meteor shower is when something hits a huge rock, and then little rocks form, and come to earth or stay in space, and make shooting stars in the sky.