sector

noun

1.
a plane figure bounded by two radii and the included arc of a circle
Derived from:
sectorial
2.
a social group that forms part of the society or the economy
3.
a particular aspect of life or activity
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