The "Centre of curvature" refers to a concept related to the curvature of a curved surface. It is the point at which the curvature is the maximum, and is the centre of a circle that best approximates the curvature of the surface at that point. Synonyms for the term "Centre of curvature" include "curvature centre," "radius centre," and "center of sphere." The term is commonly used in mathematics and physics, especially in the study of optics. Understanding the concept of the "Centre of curvature" is essential in understanding the properties of curved surfaces, such as lenses and mirrors, and their effect on the propagation of light.