No, it is a plural proper noun. Here, the word African is the demonym for a person from or in Africa. It can be a proper adjective, but not as a plural.
Kentuckian is the proper adjective for Kentucky.
Africa - African
African is an adjective meaning "of Africa". In this case the adjective indicates the source of the music.
A proper adjective is an adjective formed from a proper noun. "Arabian", "Grecian", "Japanese", "African".
Egyptian is the proper adjective for Egypt.
The noun 'African' is a proper noun, a word for a person or thing of or from the continent of Africa.The adjective 'African' is a proper adjective, a word used to describe a noun as of or from the continent of Africa.
Middle Eastern is the only proper adjective in the sentence above. It describes "greenhouses."
The proper adjective for southwest is "southwestern."
The proper adjective is Haitian.
The proper adjective for Portuguese is "Portuguese."
A house in Africa is an African house. The word African is a proper adjective to describe the common noun house.