A well rounded line (4)
I believe the answer is:
loop
This might be a double definition.
'a well' is the first definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'rounded line' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for loop that I've seen before include "Endless film strip" , "Shape produced by a curve crossing itself" , "I cross myself" , "Complete circuit; encircle" , "ring road, say" .)