arc

arc — noun

1. a smooth curved line that looks like a slice taken from a circle's edge — or any

1.nounC1
Definition

a smooth curved line that looks like a slice taken from a circle's edge — or any object that bends into this kind of rounded shape.

Example

The rainbow formed a perfect arc above the green hills near Hualien.

noun in main clause: an arc of [thing]

Ravi drew a wide arc on the whiteboard to show the planet's path.

collocation: draw an arc

Common collocations
  • draw an arc
  • form an arc
  • in a wide arc
  • graceful arc
  • perfect arc
Synonyms
  • curve

    more general; any bend, not necessarily part of a circle

  • arch

    a curved structure (like a doorway), not just the line

Antonyms

Grammar Patterns

arc of [noun]

in an arc

Usage Note

Often paired with adjectives that describe the curve's shape or width: wide, tight, gentle, graceful. Distinguish from sense 3, which is figurative and refers to a story line, not a physical curve.

Common Mistakes

The bridge has an arch shape called arc.
The bridge has a curved shape, like an arc.
'arc' is the line itself, not a name for the architectural form (which is 'arch').

2. a strong, bright stream of electricity that jumps through the air from one metal

2.nounC1
Definition

a strong, bright stream of electricity that jumps through the air from one metal point to another, giving off intense heat and light.

Example

A blue electric arc jumped between the loose wires inside the broken machine.

collocation: electric arc

The welder lowered his mask as a bright arc lit up the workshop.

collocation: bright arc; welding context

Common collocations
  • electric arc
  • arc welding
  • arc between electrodes
Synonyms
  • spark

    smaller, briefer flash of electricity

  • discharge

    technical; the release of electrical energy

Grammar Patterns

an arc of electricity

an electric arc

Usage Note

Subject is usually the spark itself; the action verbs are 'jump', 'flash', 'form'. Frequently used with 'electric' to make the meaning unambiguous, since 'arc' alone often suggests sense 1.

Common Mistakes

The lightning made a long arc on the ground.
The lightning made a long arc across the sky.
an electric arc travels through air or gas between two points, not along a surface.

3. the path that a story or one character follows from beginning to end, especially

3.nounC1
Definition

the path that a story or one character follows from beginning to end, especially inside a longer film, novel, or TV series.

Example

The writers spent months planning the villain's arc across the new season.

collocation: character / villain's arc

Tova cried at the end because the heroine's arc finally felt complete.

pattern: [character]'s arc

Common collocations
  • story arc
  • character arc
  • redemption arc
  • narrative arc
  • complete an arc
Synonyms
  • storyline

    the events themselves; arc emphasises shape and growth

  • plot

    the full sequence of events; arc is one thread inside it

Grammar Patterns

story arc

character arc

the arc of [story / character]

Usage Note

Almost always preceded by a noun showing whose arc it is ('character arc', 'story arc', 'redemption arc') or a possessive. Distinguish from sense 1: this sense is metaphorical and describes development over time, not a visible curve.

Common Mistakes

I love the arc of his face in this drama.
I love the character arc of the detective in this drama.
'arc' for stories must refer to development, not physical features.

arc — verb

Word family

  • arch
    nounB2
  • arched
    adjectiveB2
  • archway
    nounB2

Synonym discussion

Sense: noun/1

All four words describe shapes that bend, but they differ in what they refer to. 'Curve' is the most general: any line that is not straight, in any direction. 'Arc' is more specific — it suggests a smooth section of a circle's edge, often used in maths, sports, and descriptions of flying objects ('the ball traced an arc'). 'Arch' refers to a three-dimensional structure built in this curved shape, like a doorway, a bridge, or the inside of a foot — not the line itself. 'Bow' suggests a wider, flatter curve, often of something flexible bending under tension, like a branch or a wooden weapon. Compare: 'The road has a gentle curve' (any bend), 'The stone bridge has three arches' (built structures), 'The cat's back formed a perfect arc' (a clean half-circle shape).

arc ↗arch ↗curve ↗bow ↗

Common collocations

Nouns

  • story arc
  • character arc
  • electric arc
  • arc welding
  • arc lamp

Adverbs

Phrases

  • in a wide arc
  • follow an arc
  • trace an arc
  • draw an arc
  • complete an arc

Prepositions

Etymology

LatinOld FrenchMiddle EnglishModern English

Arc comes from Latin 'arcus', meaning a bow (the weapon) or anything bent into a curve. It travelled through Old French as 'arc' before settling into English in the late 1300s, first used in geometry to name part of a circle's edge. The electrical sense appeared in the 1800s when scientists noticed that sparks jumping between two points traced a glowing curved line, and the figurative 'story arc' meaning grew much later, in 20th-century film and television writing, borrowing the idea of a shape that rises and falls.