expanse vs land area

expanse and land area both are nouns.

Word	Noun	Adjective	Verb	Adverb
expanse	Yes	No	No	No
land area	Yes	No	No	No

As nouns, land area is a hyponym of expanse; that is, land area is a word with a more specific, narrower meaning than expanse:

expanse: the extent of a 2-dimensional surface enclosed within a boundary
land area: an area of ground used for some particular purpose (such as building or farming)

Other hyponyms of expanse include acreage, footprint, erasure, blank space, place, space, space, balk, baulk, plane section, section.

expanse (noun)	land area (noun)
the extent of a 2-dimensional surface enclosed within a boundary	an area of ground used for some particular purpose (such as building or farming)
a wide scope
a wide and open space or area as of surface or land or sky