Proxy

Proxy has different meanings when talking about different subjects:

Basically, "proxy" means "stands for".
In computing, a proxy server  is a server which clients use to access other computers.
A proxy marriage is when two people are getting married separately, but are getting married to one another.
A proxy murder is when a person murders on behalf of someone else.
A proxy vote is when a person votes on behalf of someone else, usually occurring in public and private companies requiring votes for decisions.
A web proxy is a server that fetches web pages for a user. Web proxies often hide your browser history and can bypass local internet restrictions.