ETYM Old Eng. cercle, French cercle, from Latin circulus (Whence also AS. circul), dim. of circus circle, akin to Greek krikos, kirkos, circle, ring. Related to Circus, Circum-.
Perfectly round shape, the path of a point that moves so as to keep a constant distance from a fixed point (the center). Each circle has a radius (the distance from any point on the circle to the center), a circumference (the boundary of the circle), diameters (straight lines crossing the circle through the center), chords (lines joining two points on the circumference), tangents (lines that touch the circumference at one point only), sectors (regions inside the circle between two radii), and segments (regions between a chord and the circumference).
The ratio of the distance all around the circle (the circumference) to the diameter is an irrational number called p (pi), roughly equal to 3.1416. A circle of radius r and diameter d has a circumference C = pd, or C = 2pr, and an area A = pr2. The area of a circle can be shown by dividing it into very thin sectors and reassembling them to make an approximate rectangle. The proof of A = pr2 can be done only by using integral calculus.
1. A plane curve generated by one point moving at a constant distance from a fixed point.
2. Something approximating the shape of a circle.
3. Any circular or rotating mechanism; SYN. round.
4. A curved section or tier of seats in a hall or theater or opera house; usually the first tier above the orchestra; SYN. dress circle.
Geometrijska slika okruglog oblika.
Manji, zatvoren krug ljudi, koji su se, posle drugog svetskog rata, bavili političkim obrazovanjem koristeći grupni rad (rus.)