A rubber spanner! (6)
I believe the answer is:
bridge
This might be a double definition.
'a rubber' is the first definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'spanner' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for bridge that I've seen before include "Structure spanning a divide" , "Span, connecting structure" , "Crossing point" , "Structure carrying a road, railway etc." , "Viaduct" .)