A device on the Internet running the Haven software, with a full copy of the Haven blockchain, actively assisting the Haven network. A node that is not running on your local machine is called @remote-node. Remote nodes can be private, if they are for personal use only, or open, if they are accessible by other people.
Nodes participate in the Haven network and secure @transactions by enforcing the rules of the network. Nodes download the entire @blockchain to know what transactions have taken place. Nodes assist the network by relaying transactions to other nodes on the network. Nodes may also choose to contribute to the Haven network by participating in crafting @blocks (this is called @mining).
Mining is the process by which nodes create a block from the previously accepted block, transactions that are waiting to be processed in the transaction pool, and the @coinbase-transaction. When a node believes it has crafted a valid block it will transmit the completed block to other nodes on the network and those nodes signal agreement by working on the next block in the chain.
The rules that nodes follow are built into the Haven software; When all nodes agree about the rules to follow this is called @consensus. Consensus is necessary for a cryptocurrency because it is how the blockchain is built; If nodes don't agree about which blocks are valid, for example people who have not updated their Haven software, those nodes that don't agree will no longer be able to participate in the Haven network.
The Haven Core Team plans for a network upgrade roughly every 6 months. At that time, if you are running a node it must be updated to the most recent version of the Haven software or it will no longer be able to participate in the network.