Arc

Arc is a term with multiple meanings across mathematics, storytelling, engineering, and technology.

In geometry, an arc is any connected portion of a curve between two endpoints; a circle’s arc is the portion of its circumference between two points. For a circle of radius r, the length of the arc corresponding to a central angle theta (in radians) is L = r theta. Arcs are described as minor or major, depending on whether they span less than or more than a semicircle, and a semicircular arc subtends 180 degrees. In many mathematical texts, the measure of an arc equals the measure of its central angle in degrees.

In graph theory and computer science, an arc denotes a directed edge from one vertex to another, as opposed to an undirected edge.

In storytelling and narrative arts, an arc refers to the structured progression of a story or a character’s development, moving from setup through conflict to resolution.

In electrical engineering and lighting, an arc is an electrical discharge through air between conductive electrodes. Arc discharges power systems, and are harnessed in arc welding, plasma torches, and older arc lamps.

In modern technology, Arc is also the name of various products, notably Arc, a web browser released by The Browser Company, and Arc, a small Lisp-like programming language used for teaching and experimentation.