A **circle** is a simple shape of Euclidean geometry that is the set of all points in the plane that are equidistant from a given point, the centre. The distance between any of the points and the centre is called the radius.

A circle is a simple closed curve which divides the plane into two regions: an interior and an exterior. In everyday use, the term "circle" may be used interchangeably to refer to either the boundary of the figure, or to the whole figure including its interior; in strict technical usage, the circle is the former and the latter is called a disk.

A circle can be defined as the curve traced out by a point that moves so that its distance from a given point is constant.

A circle may also be defined as a special ellipse in which the two foci are coincident and the eccentricity is 0. Circles are conic sections attained when a right circular cone is intersected by a plane perpendicular to the axis of the cone.

Read more about Circle: Terminology, History, Properties, Circle of Apollonius, Circles Inscribed in Or Circumscribed About Other Figures, Circle As Limiting Case of Other Figures

### Other articles related to "circle, circles":

**Circle**of The Black Thorn

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### Famous quotes containing the word circle:

“Perchance we may,

Where now this night is day,

And even through faith of still averted feet,

Making full *circle* of our banishment,

Amazed meet;”

—Coventry Kersey Dighton Patmore (1823–1896)

“The passion of love is essentially selfish, while motherhood widens the *circle* of our feelings.”

—Honoré De Balzac (1799–1850)

“It is a good lesson—though it may often be a hard one—for a man who has dreamed of literary fame, and of making for himself a rank among the world’s dignitaries by such means, to step aside out of the narrow *circle* in which his claims are recognized, and to find how utterly devoid of all significance, beyond that *circle*, is all that he achieves, and all he aims at.”

—Nathaniel Hawthorne (1804–1864)