Definition
A Proxy is an intermediary server between a user and a network service that can control, filter or modify traffic according to defined rules.
Human Explanation
Instead of connecting directly to a service, the user communicates through an intermediary server.
Why it Matters
A Proxy supports traffic control, security and enforcement of organisational security policies.
Conceptual Boundary
A Proxy is not a Firewall, although the two can work together and complement one another.
Practical Perspective
A Proxy can improve both the security and performance of network communication.