Where a map-reader's only way is up (5,4)
I believe the answer is:
south pole
'where a map-reader's only way is up' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.
This is all the clue.
Can you help me to learn more?
(Other definitions for south pole that I've seen before include "Antarctic" , "Goal of explorers" , "gets very cold!" , "Amundsen got there first, before Scott" , "to which Scott came" .)