| A | B |
|---|
| Circle | The set of all points equidistant from a given point |
| Center | The point that is equidistant from all points on the circle. |
| Radius | A line segment that has one endpoint at the center of the circle and the other endpoint on the circle |
| Diameter | A chord that passes through the center of a circle |
| Chord | A line segment whose endpoints lie on the circle |
| Secant | A line that intersects the circle in two points |
| Tangent | A line that intersects a circle in one and only one point |
| Point of tangency | The point where a line touches a circle at one point only |
