sector

American  

[sek-ter] / ˈsɛk tər /

noun

• sectors
  plural

1. Geometry. a plane figure bounded by two radii and the included arc of a circle.

2. a distinct part, especially of society or of a nation's economy.

   the housing sector; the educational sector.

3. a section or zone, as of a city.

4. Military. a designated defense area, usually in a combat zone, within which a particular military unit operates and for which it is responsible.

5. a mathematical instrument consisting of two flat rulers hinged together at one end and bearing various scales.

6. Machinery. a device used in connection with an index plate, consisting of two arms rotating about the center of the plate and set to indicate the angle through which the work is indexed.

7. Astronomy. an instrument shaped like a sector of a circle, having a variable central angle and sights along the two straight sides, for measuring the angular distance between two celestial bodies.

8. Computers. a portion of a larger block of storage, as 1/128 of a track or disk.

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verb (used with object)

1. to divide into sectors.

sector British  

/ ˈsɛktə /

noun

1. a part or subdivision, esp of a society or an economy

   the private sector

2. geometry either portion of a circle included between two radii and an arc. Area: 1/ 2 r ²θ, where r is the radius and θ is the central angle subtended by the arc (in radians)

3. a measuring instrument consisting of two graduated arms hinged at one end

4. a part or subdivision of an area of military operations

5. computing the smallest addressable portion of the track on a magnetic tape, disk, or drum store

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sector Scientific  

/ sĕk′tər /

1. The part of a circle bounded by two radii and the arc between them.

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Other Word Forms

Derived Forms

• subsector
  noun
• sectoral
  adjective

Inflected Forms

Nouns

• sectors
  plural

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Etymology

Origin of sector

First recorded in 1560–70; from Late Latin, from Latin: “cutter,” from sec(āre) “to cut, divide” + -tor -tor

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Explanation

Sector sounds like section, doesn't it? That's a good way to remember that a sector is a specific part of society or the economy, made up of similar elements — like the health care sector or the education sector. Our most common use of the word sector refers to a society’s divisions. For example, our economy is divided into the private sector (privately-owned interests) and the public sector (government). Other than that, the word also has many technical applications in math and science. From the Latin verb secare, "to cut," sector was applied long ago to math as a section of a circle, which carried through to military language as "a circle around a headquarters."

Example Sentences

See Examples For:

sector sectors

Hong Leong maintains an overweight rating on the Malaysian telco sector, pegging Telekom Malaysia and CelcomDigi as its top picks.

From The Wall Street Journal ● Oct. 16, 2026

The series joins a wave of recent films and TV shows exploring and confronting the rapidly evolving tech sector.

From Los Angeles Times ● Oct. 16, 2026

Barclays continues to recommend a portfolio with a balanced sector allocation, especially as they no longer view AI stocks as a “one-way trade.”

From MarketWatch ● Oct. 16, 2026

The AI chip leader was defying the ongoing sector slump early Friday.

From Barron's ● Oct. 16, 2026

He spread Wylan’s drawing of the prison sector between them.

From "Six of Crows" by Leigh Bardugo

Among other sectors, spending on defense military programs increased by $48 billion, or six percent, over the year to $917 billion.

From Barron's ● Oct. 16, 2026

Even so, the U.S. is better placed than many other countries to deal with those challenges, thanks to its large AI and energy sectors.

From The Wall Street Journal ● Oct. 15, 2026

But she said the production and construction sectors shrank over the three-month period.

From BBC ● Oct. 15, 2026

In our call of the day, Inui thinks unexpected earnings strength could show up in sectors and stocks where investors least expect, and might just drive a hoped-for broadening of stock-market performance.

From MarketWatch ● Oct. 14, 2026

It never ceases to amaze me how quickly he gets around the sectors.

From "Legend" by Marie Lu

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Related Words

• district
• part
• region
• zone

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