The term "normal curvature" refers to the curvature of a surface at a given point along a line that is perpendicular to that surface. Synonyms for normal curvature include Gaussian curvature, geodesic curvature, and principal curvature. Gaussian curvature is the measure of curvature at a point on a surface, regardless of the direction. Geodesic curvature is the curvature of a curve that follows the surface, while principal curvature refers to the maximum and minimum curvatures of the surface at a given point. In essence, all of these synonyms refer to different measures or types of curvature at a point on a surface, highlighting the complex and nuanced ways in which we can understand and describe the shape of objects in our world.