expanse vs surface area

expanse and surface area both are nouns.

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

As nouns, expanse and surface area are synonyms defined as:

expanse and surface area: the extent of a 2-dimensional surface enclosed within a boundary

Other synonyms of expanse include area.

expanse (noun)	surface area (noun)
the extent of a 2-dimensional surface enclosed within a boundary	the extent of a 2-dimensional surface enclosed within a boundary
a wide scope
a wide and open space or area as of surface or land or sky