# Node

In general, a node is a localized swelling (a "knot") or a point of intersection (a vertex).
Node may refer to:

## In mathematics

* Vertex (graph theory), a vertex in a mathematical graph
* Vertex (geometry), a point where two or more curves, lines, or edges meet.
* Node (autonomous system), behaviour for an ordinary differential equation near a critical point
* Singular point of an algebraic variety, a type of singular point of a curve

## In science and engineering
### Spherical geometry

* node, the points where a great circle crosses a plane of reference, or the equator of a sphere

### Astronomy

* Orbital node, the points where an orbit crosses a plane of reference
** Lunar node, where the orbits of the Sun and Moon intersect
** Longitude of the ascending node, how orbital nodes are parameterized

### Biology

* Lymph node, an immune system organ used to store white blood cells
* Node of Ranvier, periodic gaps in the insulating myelin sheaths of myelinated axons
* Sinoatrial node and atrioventricular node, specialized tissues in the heart responsible for initiating and coordinating the heartbeat
* Primitive knot or primitive node, the organizer tissue for gastrulation in vertebrates
* The place on a plant stem where a leaf is attached
* In cladistics, a shared ancestor (also see Clade)

### Computing and electronics

* Node (networking), a point of connection in a communication network
* An entity in a mesh network
* Node (circuits), a region in an electrical circuit where there is no change in potential
* Node (computer science), a basic unit used to build data structures
* Goal node (computer science), a node in a graph that meets defined criteria for success or termination
* Node (UML), the representation of a computational device in the Unified Modeling Language
* Node.js, a JavaScript-based, cross-platform runtime environment
* NodeB, hardware that is connected to the mobile phone network
* NODE (wireless sensor), a wireless handheld sensor for smart devices
* Node, a shorthand used to designate a semiconductor fabrication process

### Linguistics

* Node (linguistics), a branch point in the Tree model, or Node Theory, of language evolution

### Physics

* Node (physics), a point along a standing wave where the wave has minimal amplitude

### Space-station modules

* Unity (ISS module) or Node 1, one of the first modules of the International Space Station
* Harmony (ISS module) or Node 2, module of the International Space Station
* Tranquility (ISS module) or Node 3, a module of the International Space Station with the Cupola
* Node 4, a proposed module of the International Space Station
* Prichal (ISS module), a planned module of the International Space Station to be launched in 2021

## In music

* Node (band), Italian death metal band
* Node (singer), Danish singer and hip hop artist of Kurdish origin
* Node (album), a 2015 album by Australian metalcore band Northlane

## Other uses

* Node, Kentucky
* Node tribe, a community of pastoral nomads in India and Pakistan
* Node, a transport hub in a transportation system
* Giordana Racing Team, a British cycling team, formerly named Node4-Giordana
* Node Magazine, a literary project based on the novel Spook Country by William Gibson
* New Oxford Dictionary of English, a single-volume English language dictionary, see Oxford Dictionary of English
* Node, a cyborg with a donated human face used as a guide, in "Silence in the Library" (Doctor Who)
* Node, the pommel-like part of a chalice where the stem meets the cup
* A nodal organizational structure, such as in terms of business management, see Cellular organizational structure
* Node in aroid plant - What is a node? A node is a small, brown bump on the stem of an aroid plant. It's the point where leaves and aerial roots grow. Nodes contain meristematic tissue, which is responsible for the growth of new roots and shoots.