Secant and Tangent

In geometry, when a line meets a circle, different things can happen depending on the position of the line. 

1. The line misses the circle entirely (Non-intersecting Line).

2. The line cuts through the circle at two points (Secant).

3. The line touches the circle at exactly one point (Tangent).

A secant is a straight line that passes through the circle and intersects it at two distinct points. 

line AB cuts the circle at points M and N ⇒ AB is a secant.

A tangent is a straight line that touches a circle at exactly one point only, without cutting through it. This single point where the tangent touches the circle is called the point of contact or point of tangency.

Line CD touches the circle at point P only ⇒ CD is a tangent

Point P is the point of contact.