Aid to lookout on the bridge (5-3)
I believe the answer is:
pince-nez
This clue could be a double definition.
'aid' is the first definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'lookout on the bridge' 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?
'to' acts as a link.
Can you help me to learn more?
(Other definitions for pince-nez that I've seen before include "Pair of glasses that clip on the nose, with no side-pieces" , "Pair of glasses that clip onto the nose" , "Clip-on glasses" , "Glasses clipped on to the nose" , "Glasses used to see" .)