Questions relating to onion routing, and onion routing protocols
Onion routing is a technique for routing messages in an anonymous fashion by wrapping data in several layers of encryption which are then 'peeled off' like the layers of an onion by a series of nodes called 'onion routers'.
Tor uses onion routing to route TCP traffic. In the Tor network, onion routers are called 'relays' or 'nodes'. The last relay in an onion routing chain is called an 'exit relay' and the first relay the 'guard relay' or 'entry node'.