Linien

Linien is the German plural of Linie, meaning lines. It is used to refer to long, narrow marks or boundaries and to sequences that organize space, information, or routes. The term appears across many contexts, including mathematics, geography, transportation, art, and typography.

In mathematics, a line is an abstract one-dimensional object that extends without end in both directions and has no curvature. Lines serve as fundamental building blocks in geometry, analytic geometry, and graph theory, and can be described by equations or by a set of points.

In geography and cartography, Linien designate lines that structure maps, such as latitude and longitude lines, coastlines rendered as curves but sometimes treated as lines, and political or administrative borders. Transit networks are also described as Linien to denote routes.

In transportation, Linien refer to the routes operated by a transit agency, such as buslinien, tramlinien, or subwaylinien. The term emphasizes a predefined path or sequence of stops rather than a single vehicle.

In art, design, and typography, lines are a core visual element. Linien describe the varying marks, directions, and weights that define shapes, textures, and compositions. The term also traces to the German Linie, itself from Latin linea via Old French ligne.