Sound of running water in ice field (4)
I believe the answer is:
floe
'ice field' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for floe that I've seen before include "Piece of ice at sea" , "A field of floating ice" , "Floating flat mass of ice" , "Part separated from a mass of ice" , "Sheet of ice floating in the sea" .)