Qièchù yuán shì miáoshù qūxiàn wānqū chéngdù de gōngjù.
The osculating circle is a tool for describing the degree of curvature of a curve.
Tips
usage
Mathematical / technical term. 切 alone is 'tangent'; 切触 adds 触 ('contact / touch') to mark the higher-order case where curves not only touch but agree in curvature. Compare 相切 (xiangqie) for ordinary tangency.
