IMPORTANT DEFINITIONS ABOUT CIRCLES

Circle: It is a round geometric shape.
Circunference: It's the outside part of the circle.
Center: It is the middle point of the circle.
Radius: It is the line that goes from the center to a part of the circunference.
Diameter: It is the line that goes from one part of the circunference to another passing through the center.
Hord: It is the line that goes from one part of the circunference to another without going through the center.
Arc: It is a part of the circumference.