Proxy

par procuration

(used as, or acting as, a proxy)

fondé de pouvoir

(agent or substitute authorized to act for another person)

mandataire

(agent or substitute authorized to act for another person)

mesure indirecte

((science) measurement of one physical quantity that is used as an indicator of the value of another)

procuration

(authority to act for another, especially when written)

proxy

((software) an interface for a service)