sector

(noun) a plane figure bounded by two radii and the included arc of a circle.

(noun) a social group that forms part of the society or the economy. Example: "The public sector."

(noun) a particular aspect of life or activity. Synonyms: sphere. Example: "He was helpless in an important sector of his life."

(noun) the minimum track length that can be assigned to store information; unless otherwise specified a sector of data consists of 512 bytes.

(noun) a portion of a military position.

(noun) measuring instrument consisting of two graduated arms hinged at one end.