1. the circle that touches a curve (on the concave side) and whose radius is the radius of curvature;

[syn: circle of curvature, osculating circle]

WordNet (r) 3.0 (2006):

osculating circle n 1: the circle that touches a curve (on the concave side) and whose radius is the radius of curvature [syn: circle of curvature, osculating circle]