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

As the technologies mature, they could strengthen the commercial space sector by opening new markets, reducing costs, expanding customer choice, and introducing entirely new capabilities for space operations.

From Science Daily ● Jul. 15, 2026

A years-long crisis in the property sector and a persistent slump in domestic spending have left leaders reliant on exports to meet growth targets.

From Barron's ● Jul. 15, 2026

Swiss luxury group Richemont reported better-than-expected sales for its most recent quarter, bolstered by its jewelry business and despite a volatile market for the luxury sector.

From The Wall Street Journal ● Jul. 15, 2026

The departures began in October, when Zach Seidl, Bass’ longtime deputy mayor of communications, left for the private sector.

From Los Angeles Times ● Jul. 15, 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

"As long as it does not pose systemic risks, the government is happy to stabilise the market and gradually let other sectors play a more important role in the economy," Ng added.

From Barron's ● Jul. 15, 2026

Unified has 72 pathways available to students across 15 different industry sectors.

From Los Angeles Times ● Jul. 14, 2026

But thanks to the energy and tech sectors, expectations have actually climbed heading into second-quarter results.

From The Wall Street Journal ● Jul. 12, 2026

Hardware, memory, power equipment, utilities and grid modernization — areas all tied to the data-center buildout needed for AI — are among the other sectors that have benefited as demand has outstripped supply, said Almeida.

From MarketWatch ● Jul. 12, 2026

In both sectors, the attacks were preceded by the discharge of chlorine gas—the first time poison gas had been used by the Allies.

From "The War to End All Wars: World War I" by Russell Freedman

Related Words

• district
• part
• region
• zone