Large African river or middle-sized English one (5)
I believe the answer is:
zaire
'middle-sized english one' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Maybe there's a link between them I don't understand?
'large african river' is the wordplay.
'large african' becomes 'z' (I can't justify this - if you can you should give a lot more credence to this answer).
'river' becomes 'aire' (River Aire in Yorkshire).
'z'+'aire'='ZAIRE'
'or' is the link.
Can you help me to learn more?
(Other definitions for zaire that I've seen before include "Former African country name" , "Democratic Republic of the Congo, formerly" , "Until 1997 the name of the Democratic Republic of the Congo" , "Democratic Republic of Congo's former name" , "Former African republic" .)