There are 2 main definitions of arc in English:

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arc 1

Pronunciation: /ɑːk/


1A part of a curve, especially a part of the circumference of a circle: the point where a tangential line touches the arc of a circle
More example sentences
  • He used arcs of great circles instead of arcs of parallel circles on the sphere.
  • These jumps from one number to the next can be visualized as arcs of circles along a number line.
  • Draw three arcs of circles, with each arc having as its center one of the triangle's corners and as its endpoints the other two corners.
1.1A shape or structure resembling an arc: the huge arc of the sky
More example sentences
  • On a clear day you can see Ben Nevis in the west and Buchan Ness in the east and beyond Corryhabbie Hill on the opposite side of Glen Rinnes Lochnager and the arc of the Cairngorms form the distant horizon.
  • Beyond Corryhabbie Hill on the opposite side of Glen Rinnes, Lochnager and the arc of the Cairngorms form the distant horizon.
  • She walked through the entrance, which was a huge arc of blooming roses, and at once was overwhelmed with the beauty and the smell of the roses.
1.2A curving trajectory: he swung his torch in a wide arc
More example sentences
  • Inhale slightly more than usual and hold your breath as you lower the weights in a wide arc out to your sides.
  • Start with the dumbbells at arm's length above your chest and lower them in a wide arc out to your sides until you feel a stretch in your chest.
  • But I made it safely through the bracken and out the other side, and cut a wide arc back towards the car to continue my journey through the fields and flowers and trees.
1.3 [as modifier] Mathematics Indicating the inverse of a trigonometrical function.
From the former method of defining trigonometrical functions by arcs
Example sentences
  • Using radian measure explains why the inverse-tangent function is also called the ARCtan function - it returns the arc angle when given a tangent.
  • If we use an angle h, the arc length will be krh, where k is a constant that depends on the units of angle you use.
  • The other arc functions, acos, and atan, behave as their more-familiar counterparts.
2A luminous electrical discharge between two electrodes or other points: modern welding generators are designed so that there is a high voltage for striking the arc
More example sentences
  • The heat required in this process is generated by electric arcs struck between carbon electrodes and the metal bath.
  • Scientists later demonstrated that fullerenes can be conveniently generated by setting up an electric arc between two graphite electrodes.
  • In the bottom of the container there was a reservoir of water, and above it an apparatus caused electrical arcs to crackle.
3(In a novel, play, or film) the development or resolution of the narrative or principal theme: his transformation provides the emotional arc of the story
More example sentences
  • Today I thus have only the vaguest idea of the story of King David, the basis for the arc of Kings.
  • However the Season 1 Box Set is broken up into three distinct story arcs over the course of its thirteen episodes.
  • Anyway, using James's formula to calculate Griffey's chance of reaching 756 HRs, we can trace the arc of his career.

verb (arcs, arcing /ˈɑːkɪŋ/, arced /ɑːkt/)

[no object]
1 [with adverbial of direction] Move with a curving trajectory: the ball arced across the room
More example sentences
  • Trees had arced and curved towards the apex, forming great artificial archways, which consisted of more than merely wood and leaves.
  • Time slowed as the ball arced across Alan Main in the Gretna goal but dropped in front of Derek Townsley, the home centre-half, who hoofed it beyond peril.
  • The ball arced through the six-yard area and passed just in front of the incoming attackers and defenders before beating Van der Sar at his far post.
curl, curve, swerve, spin, turn;
soar, sail, fly, ascend, mount, climb
2 (usually as noun arcing) Form an electric arc: check that switches operate properly with no sign of arcing
More example sentences
  • Wires were coated with scale-like insulation materials to prevent the electricity from arcing.
  • This much mental electricity should be able to run a small city, but instead I'm more like a cut power line, arcing and sparking spasmodically.
  • Electricity was arcing across a gap of about an inch and a half and triggering a safety cut out.



minute of arc


second of arc


Late Middle English (denoting the path of a celestial object, especially the sun, from horizon to horizon): via Old French from Latin arcus 'bow, curve'.

  • A number of English words comes from Latin arcus ‘a bow, arch, or curve’, among them arc, arcade (late 17th century), and arch (Middle English). Arc was originally a term for the path of the sun or other celestial objects from horizon to horizon. Given the shape of a bow for shooting arrows, it should not be surprising that archer (Middle English) has the same Latin source. Another meaning of arch, ‘chief or principal’ (as in archbishop (Old English) or arch-enemy (mid 16th century)), has a different origin, coming from Greek arkhos ‘a chief or ruler’. This Greek word can also be seen in anarchy (mid 16th century), which literally means ‘the state of having no ruler’, in architect (mid 16th century) from archi and tektōn ‘builder’, and archipelago (early 16th century) from archi and pelagos ‘sea’. This was originally used as a proper name for the Aegean Sea; the general sense ‘group of islands’ arose because the Aegean Sea is remarkable for its large numbers of islands.

Words that rhyme with arc

ark, Bach, bark, barque, Braque, Clark, clerk, dark, embark, hark, impark, Iraq, Ladakh, Lamarck, lark, macaque, marc, mark, marque, narc, nark, Newark, park, quark, sark, shark, snark, spark, stark, Vlach

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There are 2 main definitions of arc in English:

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1 historical (In the UK) Agricultural Research Council.
2 Medicine AIDS-related complex.

For editors and proofreaders

Line breaks: ARC

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