Answer:
Circle: A geometric shape consisting of all points that are equidistant from a central point called the center.
Center: The point inside a circle from which all points on the circumference are equidistant.
Circumference: The distance around the edge of a circle, which is the perimeter of the circle.
Radius: A line segment that connects the center of a circle to any point on the circle's circumference. It is also half the diameter.
Diameter: A line segment that passes through the center of a circle and has both of its endpoints on the circumference. It is twice the length of the radius.
Chord: A line segment that connects two points on the circumference of a circle. The diameter is the longest chord of a circle.
Arc: A portion of the circumference of a circle, defined by two endpoints and the arc itself.
Sector: A region of a circle enclosed by two radii and the corresponding arc.
Tangent: A line that touches the circumference of a circle at a single point without crossing it.
Secant: A line that intersects a circle at two points.
Pi (π): A mathematical constant that represents the ratio of the circumference of a circle to its diameter, approximately equal to 3.14159.
Sector Angle: The angle formed at the center of a circle by two radii, measuring the portion of the circle's circumference.
Central Angle: An angle formed at the center of a circle by two radii, with its vertex at the center.
Inscribed Angle: An angle formed by two chords or a chord and a tangent that share the same endpoint on the circumference.
Circumcircle: A circle that passes through all the vertices of a given polygon.
Incircle: A circle that is tangent to all sides of a given polygon from the inside.
Concentric Circles: Circles that share the same center but have different radii.
Annulus: The region between two concentric circles, resembling a ring.
Diameter bisector: A line that passes through the center of a circle and bisects a chord.
Semicircle: Half of a circle, typically divided along the diameter.