A tangent line curve, or surface; specifically, that portion of the straight line tangent to a curve that is between the point of tangency and a given line, the given line being, for example, the axis of abscissas, or a radius of a circle produced. See Trigonometrical function, under Function.

Touching; touching at a single point

meeting a curve or surface at a point and having at that point the same direction as the curve or surface; -- said of a straight line, curve, or surface; as, a line tangent to a curve; a curve tangent to a surface; tangent surfaces.

A line in the "direction" of the surface at the intersection point. Mathematically, the tangent is a straight line with a slope equal to the slope of the surface at the point of intersection. In the image to the right, the blue line is the tangent to the black surface at the red point of intersection. Check out this link to MathWorld for more information.

In a right triangle, the tangent of a given angle is the length of the side opposite the angle divided by the length of the side adjacent to the triangle.

In a right triangle, the ratio of the length of the side opposite an angle to the length of the side adjacent to the angle.

Tangent of Angle A = BC\AC Tan of Angle A = opposite\adjacent.

A trigonometric function of an angle which is defined as the ratio of the lengths of the leg opposite to the leg adjacent to an angle in its right triangle.