Noun
1. a plane figure bounded by two radii and the included arc of a circle
2. a body of people who form part of society or economy;
"the public sector"3. a particular aspect of life or activity;
"he was helpless in an important sector of his life"4. the minimum track length that can be assigned to store information; unless otherwise specified a sector of data consists of 512 bytes
5. a portion of a military position
6. measuring instrument consisting of two graduated arms hinged at one end