The locus of points equidistant from a fixed point.

The locus of points equidistant from a fixed point is a circle. A circle is a two-dimensional shape that is defined as a set of points that are all the same distance away from a fixed point, called the center. The distance between the center of the circle and any point on the circle is called the radius. So, when we talk about the locus of points equidistant from a fixed point, we are talking about all the points that are the same distance away from the fixed point. This creates a circular shape, with the fixed point as the center of the circle and the distance between the center and any point on the circle as the radius. Therefore, the correct answer is: circle.