Afro-Eurasia vs Old World

Afro-Eurasia and Old World both are nouns.

Word	Noun	Adjective	Verb	Adverb
Afro-Eurasia	Yes	No	No	No
Old World	Yes	No	No	No

As nouns, Afro-Eurasia and Old World are synonyms defined as:

Afro-Eurasia and Old World: regions of the world such as Africa, Europe and Asia that were known to Europeans before the discovery of the Americas which they called the New World

Other synonyms of Afro-Eurasia include Afroeurasia, Eurafrasia.

Afro-Eurasia (noun)	Old World (noun)
regions of the world such as Africa, Europe and Asia that were known to Europeans before the discovery of the Americas which they called the New World	regions of the world such as Africa, Europe and Asia that were known to Europeans before the discovery of the Americas which they called the New World