Nodes

Nodes are fundamental units in multiple disciplines, defined as points or processing units that participate in a larger structure or system. In graph theory, a node (often called a vertex) is a basic element of a graph, connected to other nodes by edges. Nodes may carry attributes and can be directed or undirected; the degree of a node is the number of incident edges, and paths describe how nodes are connected within the graph.

In computer networks, a node refers to any device or process that can send, receive, or forward information. This includes computers, servers, routers, switches, and end-user devices. Networks are composed of many nodes that collaborate to route traffic, store data, or provide services. In peer-to-peer networks, nodes often act as both clients and servers.

In distributed systems and blockchain technology, nodes run software that participates in a shared state. Full nodes maintain a complete copy of the data store and validate transactions or messages, while light nodes rely on other nodes for information. Some networks designate specialized node roles, such as validators in proof-of-stake systems, which participate in consensus and block production.

In data structures and programming, a node is an element of structures such as linked lists, trees, and graphs. A node stores data and references to other nodes, enabling traversal and organization. Linked lists use sequential links; trees encode hierarchical relationships; graphs connect nodes via edges.

The term originates from the notion of a branching structure and is widely used across computer science, mathematics, and information technology to denote a connection point or processing unit within a larger system.