What is the name of the line that contains a chord in a circle?

A line that contains a chord in a circle is referred to as a secant.

A secant is defined as a line that intersects a circle at two points. Since a chord connects two points on the circumference of the circle, any secant line that crosses the circle at these two points will contain that chord. This relationship is fundamental in circle geometry, where the secant not only intersects the circle but also serves to define the chord that lies within it.

In contrast, a tangent is a line that touches the circle at only one point and does not intersect it further, thus not containing a chord. A diameter, which is a specific type of chord, is a line segment that passes through the center of the circle and connects two points on its boundary. A radius is a line segment from the center of the circle to any point on its circumference, which does not imply the presence of a chord in the broader context, as it only connects to one boundary point rather than defining two.