Definition of "Sector" :
noun: measuring instrument consisting of two graduated arms hinged at one end
noun: a particular aspect of life or activity
"He was helpless in an important sector of his life."
noun: a social group that forms part of the society or the economy
"The public sector."
noun: a portion of a military position
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 plane figure bounded by two radii and the included arc of a circle