hemisphere vs geographic area

hemisphere and geographic area both are nouns.

Word	Noun	Adjective	Verb	Adverb
hemisphere	Yes	No	No	No
geographic area	Yes	No	No	No

As nouns, geographic area is a hypernym of hemisphere; that is, geographic area is a word with a broader meaning than hemisphere:

Other hypernyms of hemisphere include geographic region, geographical area, geographical region.

hemisphere (noun)	geographic area (noun)
either half of the cerebrum	a demarcated area of the Earth
half of the terrestrial globe
half of a sphere