Repère

Repère is a French noun meaning reference point, landmark, or frame of reference. It denotes something that helps locate, orient, or measure a person or object in space or time. The verb repérer means to mark, locate, or identify. In general usage, repères are points or features used to determine position, direction, or scale, and they can be physical, temporal, or conceptual.

In mathematics and geometry, repère refers to a coordinate system: a set that defines an origin, axes, and units to establish a context for measurement. A repère orthonormé has perpendicular axes of unit length. In common mathematics instruction, the Cartesian repère in the plane is the standard example, with the origin at (0,0) and the x and y axes.

In geography and cartography, a repère is a fixed point or landmark employed to determine location or navigation, such as a mountain, coastline, building, or beacon. In everyday language, repères also describe milestones or reference points used to gauge progress or to frame discussions, for instance repères historiques or repères temporels that anchor events in time.

The concept spans disciplines, from science and engineering to the humanities, reflecting the broad idea of a reference framework that provides stability and orientation for observation, measurement, and interpretation.