Great Pyramid vs Pyramids of Egypt

Great Pyramid and Pyramids of Egypt both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Pyramid	Yes	No	No	No
Pyramids of Egypt	Yes	No	No	No

As nouns, Great Pyramid and Pyramids of Egypt are synonyms defined as:

Great Pyramid and Pyramids of Egypt: a massive monument with a square base and four triangular sides; begun by Cheops around 2700 BC as royal tombs in ancient Egypt

Other synonyms of Great Pyramid include Great Pyramid of Giza, Pyramid.

Great Pyramid (noun)	Pyramids of Egypt (noun)
a massive monument with a square base and four triangular sides; begun by Cheops around 2700 BC as royal tombs in ancient Egypt	a massive monument with a square base and four triangular sides; begun by Cheops around 2700 BC as royal tombs in ancient Egypt