The concept Proxy refers to an entity (state or non-state) which:
receives support from a Sponsor; and
serves the interests of a Sponsor by operating on its behalf towards an objective, sometimes in the area of a distinct Host.
Since the mid-20th century, the Proxy Phenomenon has been exhibited in a number of contexts:
State Proxy – During the Cold War era, superpowers activated Proxy states and organizations to serve and represent their interests and to engage in conflict with one another. This form of Proxy avoided direct superpower confrontation and mitigated the threat of nuclear war.
Terror by Proxy – Since the 1970s and 80s, non-superpower states, often rogue or weak states, began supporting and instigating terror organizations to represent and serve their interests.