What is a chord in a circle?

A chord in a circle is defined as a line segment that has its endpoints lying on the perimeter of the circle. This means that a chord connects two points that are both located on the circle itself, effectively creating a straight line between these two points. Since the definition focuses specifically on the endpoints being on the circle, this is the most accurate description of what a chord is.

The other choices describe different concepts related to circles. For example, a line that passes through the center of the circle is referred to as a diameter when it extends across to touch the circle at both ends. Similarly, a segment connecting two points outside the circle does not fit the definition of a chord, as it does not touch the circle at all. Lastly, a line that touches the circle at just one point is known as a tangent, not a chord. Each of these alternatives highlights different properties or characteristics of circles but does not fulfill the specific criteria set for a chord.