The definition of a circle uses the undefined term _.

Answer:

The answer is point.

Explanation

1. Identify the undefined term used in the definition of a circle.
   In geometry, a circle is defined as the set of all points in a plane that are equidistant from a given point, known as the center. The term that is considered undefined in this context is “point.”
2. Conclude the answer based on the definition.
   The undefined term “point” is fundamental in defining a circle as it describes the location of the center and the points that make up the circle.