Edge Node
In short: In computer science, an edge node is a computer that acts as a gateway for the end user to establish connections with other nodes.
In computer science, an edge node is a computer that acts as a gateway for the end user to establish connections with other nodes. It sits at the boundary between users and the rest of a network, receiving their requests and passing them on.
Why it matters
Edge nodes keep the heavy or sensitive parts of a system away from direct public access while still letting users reach them. In data-processing clusters, users submit jobs through an edge node instead of logging in to the machines that store and process the data, and content delivery networks place edge servers close to users to cut response times. Blockchain services use the same idea: most wallet apps do not store the chain themselves, so they talk to gateway nodes that answer queries and relay signed transactions to the peer-to-peer network. The trade-off is dependence, because a user who relies on someone else's gateway also relies on it being honest and online.
Example
A mobile wallet needs to show a balance and send a payment. It asks a gateway node run by a service provider for the latest balance, then hands it the transaction the user signed on the phone. The node forwards the transaction to other nodes in the network, which pass it along until it is included in a block.