Radius of curvature

Radius of curvature is a term characterizing the measure of how curved, or bent, a given curve or surface is. Different disciplines have different conventions concerning its definition and use. The following articles deal with various aspects:

Radius of curvature (optics)
Radius of curvature (applications), in geodesy and materials science
The reciprocal of the curvature, in differential geometry
Radius, for a sphere (lingo)
The radius of the osculating circle in differential geometry of curves
Minimum railway curve radius