Sector

sector

The smallest unit of storage read or written on a disk. See magnetic disk.

---

sector

1. Geometry either portion of a circle included between two radii and an arc. Area: ½r²θ, where r is the radius and θ is the central angle subtended by the arc (in radians)

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

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

---

sector [′sek·tər]

(computer science)

A portion of a track on a magnetic disk or a band on a magnetic drum.

A unit of data stored in such a portion.

(civil engineering)

A clearly defined area or airspace designated for a particular purpose.

(electromagnetism)

Coverage of a radar as measured in azimuth.

(mathematics)

A portion of a circle bounded by two radii and an arc joining their end points.

(meteorology)

Something resembling the sector of a circle, as a warm sector between the warm and cold fronts of a cyclone.

---

Sector 

(1) A sector in the plane is a region bounded by two rays issuing from an interior point of a figure and by an arc of its boundary cut off by these rays. In particular, a sector of a circle is bounded by two radii and an arc cut off by the radii. The area of a sector of a circle is equal to lr/2 or πr²α /360, where l is the length of the arc, α is the central angle (in degrees) subtended by the arc, and r is the radius of the circle.

(2) A sector in space is the part of a solid bounded by a conical surface whose vertex is in the solid and by the part of the solid’s surface cut off by the conical surface. A spherical sector is an example of a sector in space.