sector
Pluralsectors
- 1A field of economic activity, grouping together businesses and organizations of one kind.
The public sector employs millions of workers across the country.
Investors shifted money into the energy sector after the announcement.
UsageUsually with a word before it: the public sector, the energy sector; often hyphenated before a noun: public-sector pay.
Similarindustry, field, sphere, branch
Note
Public and private sector form a fixed pair that splits an economy in two. Joris Luyendijk, writing in The Guardian Weekly in 2013, likens the British establishment's struggle with the financial sector to an alcoholic's denial.
- 2A distinct part of a larger area or thing, especially one marked off from the rest, such as a zone of a city, a stadium or, in science fiction, of space.
Each sector of the warehouse was assigned to a different team.
The stadium was split into numbered sectors for crowd control.
- 3An area that a military unit is responsible for defending or operating in, marked by fixed boundaries, including a division of a coastal frontier.
The battalion held its sector against repeated attacks.
Commanders divided the front into sectors, each with its own orders.
Note
In military use the word carries responsibility as well as ground. A sector is the stretch a unit answers for, covering its maneuver, surveillance and defense, inside a larger area of operations. That is why units are said to hold a sector: the verb is about keeping a charge, not just occupying a space. A front is divided into sectors, and each comes with its own limits and orders.
Checked 6 Nov 2026 · 4 facts
- A military sector is a bounded area for which a unit has operational and defensive responsibility, including coordination of maneuver. trngcmd.marines.mil
- Sectors can be subdivisions of a larger area of operations and carry assigned surveillance responsibilities. lineofdeparture.army.mil
- A front can be divided into sectors. etheses.whiterose.ac.uk
- Sectors have assigned boundaries and operational responsibilities. rdl.train.army.mil
Less common meanings
- 4A region of a circle bounded by two radii and the arc between their endpoints.
The student calculated the area of the shaded sector.
Each sector of the pie chart represented a different expense.
Note
The pie slice of geometry, and the reason pie-chart wedges share its name. Because it reaches the center, its size follows directly from its angle: the area is half the radius squared times the central angle in radians. A sector with a quarter-turn angle is therefore exactly a quarter of the disk. Its full name is circular sector.
Checked 6 Nov 2026 · 4 facts
- Pie-chart wedges are geometric sectors. open.edu
- A sector reaches the center and is also called a circular sector. math.libretexts.org
- The sector's area is half the radius squared times its central angle in radians. openstax.org
- A quarter-turn sector occupies exactly one quarter of the disk. jwilson.coe.uga.edu
- 5A fixed-size unit of data, traditionally 512 bytes, stored in sequence on a track of a disk or other digital medium.
The repair tool scanned the drive for damaged sectors.
Each sector on the disk holds the same number of bytes.
Note
The smallest piece of a disk the hardware can address. The controller reads and writes whole sectors at a time, never part of one. The traditional size is 512 bytes, though modern drives often use 4,096-byte sectors. When people talk about bad or damaged sectors, they mean units the drive can no longer read reliably.
Checked 6 Nov 2026 · 5 facts
- A sector is the smallest addressable storage unit on a disk. en.wikipedia.org
- Physical disk reads and writes operate in whole sectors. learn.microsoft.com
- The traditional hard-disk sector size is 512 bytes. support.microsoft.com
- Modern drives commonly use 4,096-byte physical sectors. pclt.sites.yale.edu
- Bad sectors report access errors and cannot be read reliably. seagate.com
- 6A fixed, continuous section of a racetrack, where the parts do not overlap but together make up the whole lap.
The driver gained two tenths in the final sector.
Telemetry showed strong pace across all three sectors.
Note
The timing word of circuit racing. Split times are recorded at each sector boundary, so a driver's lap can be compared piece by piece with a rival's or with their own best. A lap is conventionally divided into three sectors. Commentators speak of a quick first sector, or of time lost in the final one.
Checked 6 Nov 2026 · 4 facts
- Sector boundaries are timing points used to obtain split times. help.hhtiming.com
- Sector times allow comparison with other drivers. formula1.com
- Sector times allow comparison with the driver's own best sector performance. 24h-lemans.com
- Three sectors per lap is an established convention, including in Formula One. astonmartinf1.com
- 7A portion of a sphere or solid ball bounded by a cone whose apex lies at the center.
The diagram highlighted a single sector of the sphere.
To find the volume of a spherical sector, multiply two-thirds of pi by the square of the radius and by the height of its cap.
Note
The solid counterpart of the flat pie slice: a cone with its tip at the center of a ball, capped by the curved patch of the ball's surface above its base. It looks rather like an ice-cream cone with the scoop still on. Mathematicians usually say spherical sector in full whenever the flat kind could also be meant.
Checked 6 Nov 2026 · 2 facts
- A spherical sector is the three-dimensional analogue of a circular sector. en.wikipedia.org
- The described solid has a conical portion with its apex at the ball's center and a spherical cap above its base. mathworld.wolfram.com
- 8A part of a crag that contains a group of climbing routes.
- 9A toothed gear whose working face forms the arc of a circle rather than a full ring.
- 10A calculating instrument made of two equal-length rulers joined by a hinge.
- 11A smaller community or subculture belonging to the wider world of micronations.
Very interesting read. Love it, and very inspiring. I hope this will be good for nations. I am planning in a thing like this for the MicroWiki sector, and MicroWikia sector, so this is a good model.
2012, H.A Gov, “Re: University of Directus Releases Historic Study”
Practice
Can you tell the meanings of sector apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.
Origin
Borrowed from the Latin word "sector".
Checked 6 Nov 2026 · 1 fact
- English sector was borrowed from Latin sector. en.wiktionary.org