DictionaryosculationTangential contact
noun

osculation

Contact between curves or surfaces at a point where their tangents agree.

The diagram shows osculation where two curves share a tangent.

Etymology

Latin osculatio means kissing. Geometry uses the contact image for curves or surfaces that touch with agreeing tangents, as if lightly kissing at the meeting point.

More examples

  • Their shared tangent helps us locate the point of osculation.
  • Students compare osculation with a crossing of two curves.
  • The two surfaces exhibit osculation at their point of contact.

Forms

osculation · osculations

osculate verb — Touch at a point with matching tangents.

Similar words

tangency
Describes shared tangent contact without implying closer local agreement.
contact
Means touching generally, without requiring agreement between tangents.