A reverse proxy is a type of proxy server that fetches resources from a specific defined set of servers for a client. It is used in cases when there is an advantage to not exposing the web server with the content directly whether it be for security reasons or because of a lack of available public IP addresses.
A reverse proxy is a type of proxy server. Unlike a traditional "forward proxy" server, a reverse proxy fetches resources from a specific defined set of servers for a client. The Apache HTTPD server's mod_proxy module is a popular example of software that can be used as a reverse proxy.
A reverse proxy can be used in cases when there is an advantage to not exposing the server with the content directly to the Internet, whether it be for security reasons or because of a lack of available public IP addresses.