noun / adjective
tangent
A line touching a curve with the same direction at contact.
The tangent has the same slope as the curve here.
Etymology
The Latin verb means touching. The line is named for touching the curve while sharing its direction at the contact point.
More examples
- A tangent to a circle is perpendicular to the radius at contact.
- This line is tangent to the parabola at its vertex.
- The two tangents meet outside the circle.
Forms
tangent · tangents
tangency noun — Contact between curves sharing the same direction.
tangential adjective — Directed along a tangent to a curve.