What Does RADIUS (Remote Authentication Dial-in User Service) Mean?

RADIUS is a client/server protocol that allows an end user to access a proprietary network resource remotely.

Techopedia Explains RADIUS (Remote Authentication Dial-in User Service)

RADIUS is a critical part of many network security systems, and understanding how it works is essential for anyone who is responsible for managing a network. RADIUS is a standards-based protocol, which means that it is defined by an Internet Engineering Task Force (IETF) specification.