It's in Belgium, also in Spain (3)
I believe the answer is:
spa
'spain' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for spa that I've seen before include "Mineral-water resort" , "hydro" , "here for the good of his health?" , "Boston" , "Watering place" .)