British West Africa vs district

British West Africa and district both are nouns.

Word	Noun	Adjective	Verb	Adverb
British West Africa	Yes	No	No	No
district	Yes	No	Yes	No

As nouns, district is a hypernym of British West Africa; that is, district is a word with a broader meaning than British West Africa:

British West Africa: the former British territories of western Africa, including Nigeria, Cameroon, Gambia, Togo, Sierra Leone, and the Gold Coast
district: a region marked off for administrative or other purposes

Other hypernyms of British West Africa include dominion, territorial dominion, territory.

British West Africa (noun)	district (noun)
the former British territories of western Africa, including Nigeria, Cameroon, Gambia, Togo, Sierra Leone, and the Gold Coast	a region marked off for administrative or other purposes

British West Africa (verb)	district (verb)
	regulate housing in; of certain areas of towns