Feature of river at Chiswick had to be broadcast (4)
I believe the answer is:
eyot
'feature' is the definition.
Both the definition and answer are singular nouns.
Maybe there's a link between them I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for eyot that I've seen before include "Little island in a river or lake" , "Fawlty Towers waiter" , "Islet found in a river, (especially in England)" , "Small river island" , "isle" .)