A cemetery is the land used for burials. If you are 11 and you purchase a plot in a cemetery, you are planning too far ahead.
Cemetery comes all the way from the Greek work koimētērion, which means "sleeping place." But the sleep you do in cemeteries is an eternal one. Cemeteries can often be found near churches, or in big parks outside of cities, usually gated off because the ground has been consecrated, or blessed. Sometimes we use cemetery metaphorically. The sea is a cemetery for shipwrecked sailors, just as a junk shop might be a cemetery for old shoes.