Onion Routing is a privacy-enhancing technique used to anonymize internet traffic. It works by encrypting data in multiple layers and sending it through a series of volunteer-operated servers, called nodes or relays. Each node removes one layer of encryption before passing the data to the next, making it extremely difficult for anyone to trace the origin, destination, or content of the communication. This method is the foundation of networks like Tor, which help users browse the web privately and evade censorship or surveillance.