Etymologically the word circle comes from the Latin circus, more specifically from the form circulus, which means round. Circle
A circle is a flat geometric figure bounded by a circumference, its perimeter equals the length of its circumference.
Every circle is made up of four elements: the radius, the diameter, the arc and the string
The radius is a segment from any point on the circumference to the center of the circumference. The diameter is the line or segment that joins two points on the circumference through its center. The arc is a portion or part of the circumference. And finally, the string is the segment that joins two points on the circumference. Also, when divided in two it is called a semicircle.
From a geometric point of view, there is also the tangent (line that just touches a point on the circumference that surrounds the circle) and the secant (line that touches two points on the circumference).
In everyday language the term circle is equivalent to round. It can be said that this geometric figure is very intuitive (unlike other more complex ones), since in nature there are many round shapes: planets, tree trunks, the iris of the human eye, the central part of some flowers, certain fruits, etc. The circular shape is found in many everyday objects (some very large like the Ferris wheel and others much smaller like marbles).
The idea of a circle goes beyond a simple figure of geometry or the shape of a series of objects or products
There is a whole symbology and several connotations related to the circle. When a group of people holds the power of an entity, it is called the circle of power. In a more personal sense, a group of close individuals forms a circle of friends. When an idea is expressed without a conclusion , it is often said that it is a circular argument. In many anagrams this shape is used because it is visually striking.
There are other curious senses and uses related to the round shape of the circle. When transmitting a communication among a group of people, it is customary to say that a circular was sent. When we go around to talk about something we employ a circumlocution. The place to carry out car races is a circuit. The money that circulates is called current.
Finally, the circle is a figure present in our reality , at the same time, it is part of language because it has a peculiar characteristic : it transmits movement and change.