Warm coat extended some length (7)
I believe the answer is:
furlong
'some length' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'warm coat extended' is the wordplay.
'warm coat' becomes 'fur' (fur coat is a kind of coat. I am not sure about the 'warm' bit.).
'extended' becomes 'long-' (similar in meaning).
'fur'+'long'='FURLONG'
Can you help me to learn more?
(Other definitions for furlong that I've seen before include "One-eight of a mile" , "One eighth of a mile" , "Measure of distance" , "1/8th of a mile" , "Imperial unit of length, an eighth of a mile" .)