proxy

Short definition from Wiktionary

Adjective

1. 1
   Used as a proxy or acting as a proxy.

Noun

1. 1
   An agent or substitute authorized to act for another person.
2. 2
   The authority to act for another, especially when written.
3. 3
   The written appointment of a proctor in suits in the ecclesiastical courts
4. 4
   A measurement of one physical quantity that is used as an indicator of the value of another
5. 5
   An interface for a service, especially for one that is remote, resource-intensive, or otherwise difficult to use directly.
6. 6
   Clipping of proximity mine.

Verb

1. 1
   To serve as a proxy for.
2. 2
   To function as a server for a client device, but pass on the requests to another server for service.