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

Etymology

Origin of sector

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

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

This reset for technology makes the sector more attractive relative to the rest of the market, Truist thinks.

From MarketWatch ● Sep. 18, 2026

But in recent years, the bank also has marshaled capital investments from the private sector at an unprecedented clip, according to new data it published Thursday.

From The Wall Street Journal ● Sep. 17, 2026

Dangote's sprawling refinery on the outskirts of Lagos, which began operating two years ago and now processes around 700,000 barrels of crude a day, has transformed the fortunes of Nigeria's oil sector.

From BBC ● Sep. 17, 2026

The chip sector had suffered Monday following calls over the weekend from AI leaders, including Anthropic CEO Dario Amodei and OpenAI CEO Sam Altman, to slow the pace of AI development.

From MarketWatch ● Sep. 17, 2026

The United States defied the blockade with a massive airlift of supply planes that flew over Soviet forces and directly into Tempelhof Airport in the Western sector of Berlin.

From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau

D’Amaro has said he wants the Disney+ app to be a one-stop shop for fans to engage with the company’s entertainment, sports, games and experiences sectors.

From Los Angeles Times ● Sep. 17, 2026

Gibbons said the information technology and energy sectors have proved to be the best performing on average one year after a rate rise.

From MarketWatch ● Sep. 17, 2026

Opening up effective single-market access for Canadian businesses in cutting-edge sectors like artificial intelligence, defense and the production of semiconductors or magnets is also on the table.

From The Wall Street Journal ● Sep. 16, 2026

Ursula von der Leyen told the European Parliament on Wednesday she wanted to work on "opening the door" for Canada, which would involve closer ties on various key sectors.

From BBC ● Sep. 16, 2026

I don’t bring my guns—I don’t want anyone to track me to the plague sectors.

From "Legend" by Marie Lu

Related Words

• district
• part
• region
• zone