A computer connected to the Bitcoin network using a client that relays transactions to others. Each Bitcoin client currently running within the network is referred to as a “node” of the system. These computers transmit transactions throughout the network. Also referred to as a “client” of the system. There are “full nodes” which are capable of validating the entire blockchain and “lightweight nodes”, with reduced functionality. Wallet applications which speak to a server are not considered nodes.
Malone, J.A (2015). Glossary of Bitcoin Terms and Definitions. United States: Lulu Press, Inc