A few crossing miles to war zone (5)
I believe the answer is:
somme
'war zone' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'a few crossing miles' is the wordplay.
'a few' becomes 'some' (both can mean a small amount of something).
'crossing' means one lot of letters goes inside another.
'miles' becomes 'm' (common abbreviation).
'some' placed around 'm' is 'SOMME'.
'to' is the link.
Can you help me to learn more?
(Other definitions for somme that I've seen before include "WW1 battle site" , "European river" , "Major Great War battle" , "French river, scene of 1916 battles" , "WW1 battlefield" .)