What geometric shape is defined by the set of points that are equidistant from a central point in a plane?

Circle

The circle, one of the most fundamental and universal shapes in geometry, has fascinated humans since antiquity. Its simple definition hides a deep mathematical complexity and beauty, embodied by the constant π (pi), the ratio of a circle's circumference to its diameter. This transcendental constant, though seemingly simple, has vast and profound implications in mathematics and physics. Circles are not only found in mathematics textbooks; they are ubiquitous in nature, art, and architecture, serving as powerful symbols for totality, unity, and harmony.