sector vs piece of land

sector and piece of land both are nouns.

Word	Noun	Adjective	Verb	Adverb
sector	Yes	No	No	No
piece of land	Yes	No	No	No

As nouns, piece of land is a hypernym of sector; that is, piece of land is a word with a broader meaning than sector:

Other hypernyms of sector include parcel, parcel of land, piece of ground, tract.

sector (noun)	piece of land (noun)
measuring instrument consisting of two graduated arms hinged at one end	an extended area of land
a particular aspect of life or activity
a social group that forms part of the society or the economy
a portion of a military position
the minimum track length that can be assigned to store information; unless otherwise specified a sector of data consists of 512 bytes
a plane figure bounded by two radii and the included arc of a circle