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• arc
  arc

  noun

  any unbroken part of the circumference of a circle or other curved line.
• ARC
  ARC

  noun

  AIDS-related complex.

arc

¹ American  

[ahrk] / ɑrk /

noun

1. Geometry. any unbroken part of the circumference of a circle or other curved line.

2. Also called electric arc.  Electricity. a luminous bridge formed in a gap between two electrodes.

3. Astronomy. the part of a circle representing the apparent course of a heavenly body.

4. anything bow-shaped.

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verb (used without object)

arced, arcked, arcing, arcking

1. to form an electric arc.

2. to move in a curve suggestive of an arc.

ARC ² American  

[ahrk] / ɑrk /

noun

1. Pathology. AIDS-related complex.

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ARC ³ American  

Or A.R.C.

abbreviation

1. American Red Cross.

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arc ¹ British  

/ ɑːk /

noun

1. something curved in shape

2. part of an unbroken curved line

3. a luminous discharge that occurs when an electric current flows between two electrodes or any other two surfaces separated by a small gap and a high potential difference

4. astronomy a circular section of the apparent path of a celestial body

5. maths a section of a curve, graph, or geometric figure

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verb

1. (intr) to form an arc

prefix

1. maths specifying an inverse trigonometric function: usually written arcsin , arctan , arcsec , etc, or sometimes sin–1 , tan–1 , sec–1 , etc

ARC ² British  

abbreviation

1. AIDS-related complex: an early condition in which a person infected with the AIDS virus may suffer from such mild symptoms as loss of weight, fever, etc

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arc Scientific  

/ ärk /

1. A segment of a circle.

2. See electric arc

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Etymology

Origin of arc

1350–1400; Middle English ark < Latin arcus bow, arch, curve

Explanation

An arc is a curve. You can describe the bend of a rainbow as an arc. In math, an arc is one section of a circle, but in life you can use the word to mean any curved shape, like the arc of a ballerina's arm or the graceful arc of a flowering vine over a trellis. In the 14th century, arc first meant the movement of the sun in the sky, from the Old French arc, "bow or arch," and the Latin root arcus, also "bow or arch."

Example Sentences

The results also match what engineers predicted based on ground testing in arc jet facilities.

From Science Daily • May 4, 2026

Harden had fired away 13 times from behind the arc.

From The Wall Street Journal • Apr. 28, 2026

Like a long-standing sitcom, much of Guardiola's Manchester City career follows the same story arc: a bright September before his side begin to struggle.

From BBC • Apr. 25, 2026

Stage star Patti LuPone plays a horse named Patti LuPony, involved in a long arc about a production of “Mame.”

From Los Angeles Times • Apr. 23, 2026

She hurled Kasusu toward us in a high arc.

From "City of the Plague God" by Sarwat Chadda

Related Words

• arch