What term features a straight line that cuts through a circle, touching both ends on the circumference?

The correct term for a straight line that cuts through a circle, touching both ends on the circumference, is a chord. A chord is defined as a line segment with both endpoints on the circle, and it does not necessarily have to pass through the center of the circle, which distinguishes it from a diameter.

In contrast, a diameter is a specific type of chord that goes through the center of the circle, effectively splitting it into two equal halves. An arc, on the other hand, refers to any continuous portion of the circumference of a circle, so it does not represent a line but rather a segment of the circle itself. A radius is a line segment that connects the center of the circle to any point on its circumference, which is also different from a chord since it does not connect two points on the circumference but rather the center to the circumference. Thus, the definition and characteristics of a chord align perfectly with the description provided in the question.