Definition:Tangent


 * Geometry
 * A curve is tangent to another curve if it touches that curve but does not cross it.


 * Analytic Geometry
 * A straight line is tangent to a curve if it intersects that curve locally at exactly one point.


 * Trigonometry
 * The tangent of an angle $\theta$ is a function defined as the opposite side divided by the adjacent.


 * Analysis
 * The tangent of a real number $x$ is defined as the extension of the tangent of an angle to the real numbers.


 * Complex Analysis
 * The tangent of a complex number $z$ is defined as the extension of the tangent of a real number to the complex plane.

Linguistic Note
The word tangent comes from the Latin tangentus that which is touching, the present participle of tangere to touch.

It is pronounced with a soft g: tan-jent'.