1an area or portion that is distinct from others:operations in the southern sector of the North Sea
a distinct part or branch of a nation’s economy or society or of a sphere of activity such as education:the government aimed to reassure the industrial and commercial sector
Military a subdivision of an area for military operations.
Computing a subdivision of a track on a magnetic disk.
2the plane figure enclosed by two radii of a circle or ellipse and the arc between them.
3a mathematical instrument consisting of two arms hinged at one end and marked with sines, tangents, etc. for making diagrams.
