Define the tangent of a circle and secant of a circle.

Tangent:

Tangent is a line that touches a circle at exactly one point, and the point is known as point of contact.

In the figure, EF is a tangent and G is the point of contact.

Secant:

A line passing through a circle and intersecting the circle at two points is called the secant of a circle.

In the figure AB and CD are secants.