A circle is a closed shape consisting of all points in a plane at a given distance from a given point, the center or spelled centre in some dialects. The perimeter or circumference of a circle is the length of one complete circuit around the outside edge. A perfect circle has an infinite number of sides and angles, but in practice, circles are often drawn as regular polygons with only very few sides.
Equivalently, it is the locus of all points that are equidistant from a given point. The distance between any of the points and the center is called the radius. A circle is named by its center point and has a circumference of 360 degrees. The circumference (perimeter) of a circle with a radius of r is 2πr. It encloses an area (A = πr2).
A great circle is the largest circle that can be inscribed on a planetoid surface and is the same as the shortest path between two points on that surface, i.e., along the surface of Earth it would be an airplane flightpath or oceanic route which cuts across rather than following longitudes around Earth’s curvature.
The word “circle” has its origins in the Latin word circus, which itself is derived from the Greek word kirkos. The original meaning of the word was “circle” or “ring,” but it eventually came to mean “arena” or “circus.” The first known use of the word in English was in a work by Chaucer called The Canterbury Tales, written in the 14th century.
The meaning of the word has changed over time, and it is now often used to refer to a group of people who share a common interest or activity. For example, you might say that you have a circle of friends who are all into hiking. Or you might say that your family is your closest circle. Someone may even say they are my sphere of influence.
So what does the etymology of the word tell us about its current meaning? It suggests that circles are important because they bring people together for shared activities and interests. And just as importantly, circles represent safety and security – something we all crave in our lives.