Boundless sand outside of Nigeria in semi-wild, hot biome (8)
I believe the answer is:
savannah
'boundless sand outside' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps there's a link between them I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for savannah that I've seen before include "Flat grassland in tropical or subtropical regions" , "plain [to see]" , "African grassland" , "Subtropical grassy plain" , "A grassy plain in hot regions with no trees" .)