Proxy server
A proxy server can change the information that it gives to the client, and if the same information is accessed many times or by many different clients it can use what is called a cache to make things faster. A cache is the term for information that has been accessed and saved for future use; if a proxy server has what the client is accessing in its cache, it will make it faster because it does not need to go and access the other server to provide what the client wants.