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Circle
A circle is a simple closed shape. It is the set of all points in a plane that are at a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves so that its distance from a given point is constant. The distance between any of the points and the centre is called the radius. This article is about circles in Euclidean geometry, and, in particular, the Euclidean plane, except where otherwise noted.
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 only the boundary and the whole figure is called a disc.
A circle may also be defined as a special kind of ellipse in which the two foci are coincident and the eccentricity is 0, or the two-dimensional shape enclosing the most area per unit perimeter squared, using calculus of variations.
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Circle (noun)
A two-dimensional geometric figure, a line, consisting of the set of all those points in a plane that are equally distant from a given point (center).
“The set of all points (x, y) such that (x-1)2 + y2“
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“r2 is a circle of radius r around the point (1, 0).”
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Circle (noun)
A two-dimensional geometric figure, a disk, consisting of the set of all those points of a plane at a distance less than or equal to a fixed distance (radius) from a given point.
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Circle (noun)
Any thin three-dimensional equivalent of the geometric figures.
“Put on your dunce-cap and sit down on that circle.”
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Circle (noun)
A curve that more or less forms part or all of a circle.
“move in a circle”
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Circle (noun)
Orbit.
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Circle (noun)
A specific group of persons; especially one who shares a common interest.
“inner circle;”
“circle of friends”
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Circle (noun)
A line comprising two semicircles of 30 yards radius centred on the wickets joined by straight lines parallel to the pitch used to enforce field restrictions in a one-day match.
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Circle (noun)
A ritual circle that is cast three times deosil and closes three times widdershins either in the air with a wand or literally with stones or other items used for worship.
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Circle (noun)
A traffic circle or roundabout.
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Circle (noun)
Compass; circuit; enclosure.
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Circle (noun)
An instrument of observation, whose graduated limb consists of an entire circle. When fixed to a wall in an observatory, it is called a mural circle; when mounted with a telescope on an axis and in Y’s, in the plane of the meridian, a meridian or transit circle; when involving the principle of reflection, like the sextant, a reflecting circle; and when that of repeating an angle several times continuously along the graduated limb, a repeating circle.
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Circle (noun)
A series ending where it begins, and repeating itself.
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Circle (noun)
A form of argument in which two or more unproved statements are used to prove each other; inconclusive reasoning.
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Circle (noun)
Indirect form of words; circumlocution.
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Circle (noun)
A territorial division or district.
“The ten Circles of the Holy Roman Empire were those principalities or provinces which had seats in the German Diet.”
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Circle (noun)
A bagginess of the skin below the eyes from lack of sleep.
“”After working all night, she had circles under her eyes.”
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Circle (verb)
To travel around along a curved path.
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Circle (verb)
To surround.
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Circle (verb)
To place or mark a circle around.
“Circle the jobs that you are interested in applying for.”
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Circle (verb)
To travel in circles.
“Vultures circled overhead.”
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Cycle (noun)
An interval of space or time in which one set of events or phenomena is completed.
“the cycle of the seasons, or of the year”
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Cycle (noun)
A complete rotation of anything.
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Cycle (noun)
A process that returns to its beginning and then repeats itself in the same sequence.
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Cycle (noun)
The members of the sequence formed by such a process.
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Cycle (noun)
In musical set theory, an interval cycle is the set of pitch classes resulting from repeatedly applying the same interval class to the starting pitch class.
“The interval cycle C4 consists of the pitch classes 0, 4 and 8; when starting on E, it is realised as the pitches E, G# and C.”
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Cycle (noun)
A series of poems, songs or other works of art.
“The “Ring of the Nibelung” is a cycle of four operas by Richard Wagner, the famous nineteenth-century German composer.”
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Cycle (noun)
A programme on a washing machine, dishwasher, or other such device.
“Put the washing in on a warm cycle.”
“the spin cycle”
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Cycle (noun)
A pedal-powered vehicle, such as a unicycle, bicycle, or tricycle, or a motorized vehicle that has either two or three wheels, such as a motorbike, motorcycle, motorized tricycle, or motortrike.
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Cycle (noun)
A single, a double, a triple, and a home run hit by the same player in the same game.
“Jones hit for the cycle in the game.”
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Cycle (noun)
A closed walk or path, with or without repeated vertices allowed.
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Cycle (noun)
A chain whose boundary is zero.
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Cycle (noun)
An imaginary circle or orbit in the heavens; one of the celestial spheres.
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Cycle (noun)
An age; a long period of time.
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Cycle (noun)
An orderly list for a given time; a calendar.
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Cycle (noun)
One entire round in a circle or a spire.
“a cycle or set of leaves”
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Cycle (verb)
To ride a cycle.
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Cycle (verb)
To go through a cycle or to put through a cycle.
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Cycle (verb)
To turn power off and back on
“Avoid cycling the device unnecessarily.”
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Cycle (verb)
To maintain a team’s possession of the puck in the offensive zone by handling and passing the puck in a loop from the boards near the goal up the side boards and passing to back to the boards near the goal
“They have their cycling game going tonight.”
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Circle (noun)
a round plane figure whose boundary (the circumference) consists of points equidistant from a fixed point (the centre)
“draw a circle with a compass”
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Circle (noun)
something in the shape of a circle
“the lamp spread a circle of light”
“they all sat round in a circle”
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Circle (noun)
a dark circular mark below each eye caused by illness or tiredness
“she was pale and rather beautiful, with dark circles around deep, exhausted eyes”
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Circle (noun)
a curved upper tier of seats in a theatre or cinema
“she sat in the front row of the circle”
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Circle (noun)
short for striking circle
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Circle (noun)
a group of people with a shared profession, interests, or acquaintances
“she did not normally move in such exalted circles”
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Circle (verb)
move all the way around (someone or something), especially more than once
“they were circling Athens airport”
“we circled round the island”
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Circle (verb)
move in a wide loop back towards one’s starting point
“he paced away from her, then circled back”
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Circle (verb)
form a ring around
“the abbey was circled by a huge wall”
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Circle (verb)
draw a line around
“circle the correct answers”