Battle with Few protecting millions? (5)
I believe the answer is:
somme
'battle' is the definition.
(Somme is an example)
'few protecting millions?' is the wordplay.
'few' becomes 'some' (associated in meaning).
'protecting' indicates putting letters inside (inserted letters are held or protected).
'millions?' becomes 'm' (abbreviation).
'some' going around 'm' is 'SOMME'.
'with' acts as a link.
(Other definitions for somme that I've seen before include "Scene of WW One battles" , "French river known from World War 1" , "French river known from First World War" , "Move in clumsy bounds" , "Major Great War battle" .)