Fish out of river from which scales hang (4)
I believe the answer is:
beam
This clue could be a double definition.
'fish out of river' is the first definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'from which scales hang' is the second definition.
(part of a set of scales)
Can you help me to learn more?
(Other definitions for beam that I've seen before include "Ray - large piece of wood" , "Smile, transmit (radio signal)" , "Horizontal structural member" , "A broad smile like lunar ray" , "Smile radiantly" .)