Usually the two lines are the arms of an angle, as in the figure above, but this is not always the case. For example, in the figure at right, two secant lines cut off, or intercept, two arcs, AB and CD.
When two straight lines cross a circle, the part of the circle between the intersection points is called the intercepted arc. The lines intercept, or 'cut off', the arc.
Usually the two lines are the arms of an angle, as in the figure above, but this is not always the case.
For example, in the figure at right, two
secant
lines cut off, or intercept, two arcs, AB and CD.