Identical vs. Equal


On page 140 it is talking about in some classes like NSString, there is a difference between equal and identical. It describes the word identical as if the x and y have the same address. What does it mean by address? This may be a dumb question but I know this is important so I want to know what I am doing! and Also can someone just put the description of Identical vs. Equal in simpler terms for me That would be awesome! Thanks in advance