Proxy

Proxy may refer to something which acts on behalf of something else as in:

Proxy server, a computer network service that allows clients to make indirect network connections to other network services;
Proxy pattern, a software design pattern in computer programming;
Proxy (climate), a measured variable used to infer the value of a variable of interest in climate research;
Proxy murder, a murder in which the murderer does so at the behest of another
Proxy war, a war where two powers use third parties as a substitute for fighting each other directly;
Proxy statement, an announcement of and an invitation to a U.S. stockholders' meeting;
Proxy fight, an event that may occur when opposition develops to a corporation management among its stockholders;
Proxy marriage, a practice formerly common amongst European monarchs, where one party is not present in person to their marriage to the other.