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

Earlier this month, the European Central Bank warned that “the rise of AI has driven a blistering rally in the tech sector, bringing stock market valuations to levels last seen during the dot-com bubble.”

From MarketWatch ● Aug. 29, 2026

“China’s energy sector must maintain bottom-line and extreme-scenario thinking.”

From The Wall Street Journal ● Aug. 29, 2026

Cars, trucks and parts are among the main goods traded between the US, Canada and Mexico, with the manufacturing sector and supply chains stretching across borders.

From BBC ● Aug. 29, 2026

Job openings, as tracked by both the government and the private sector, rebounded early in the year and appeared to suggest companies might ramp up hiring.

From MarketWatch ● Aug. 29, 2026

Keeth had parlayed his skills and work ethic from fencing into an MBA from Columbia University and a job in the financial sector.

From "Proud" by Ibtihaj Muhammad

We collaborate closely with various sectors in the food industry, from farmers to food companies, to help implement effective mycotoxin management integrated within food safety standards.

From Science Daily ● Aug. 28, 2026

While the move from agriculture to office work took generations, sectors like law, customer service, software and manufacturing will feel AI’s impact over the course of a decade.

From The Wall Street Journal ● Aug. 26, 2026

Most job growth in recent years has come in sectors reflecting Japan’s ageing demographic, such as healthcare, medical and welfare.

From MarketWatch ● Aug. 26, 2026

Announcing the new economic measures, Bessent said expanded secondary sanctions would target Iran's digital assets and its technology, gold, aviation and shipping sectors.

From Barron's ● Aug. 26, 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