Soldiers, old, left in shade (7)
I believe the answer is:
parasol
'shade' is the definition.
(I know that parasol is a type of shade)
'soldiers old left' is the wordplay.
'soldiers' becomes 'paras' (para is a kind of soldier).
'old' becomes 'o' (abbreviation).
'left' becomes 'l' (common abbreviation).
'paras'+'o'+'l'='PARASOL'
'in' is the link.
(Other definitions for parasol that I've seen before include "It's put up to provide shade" , "aeroplane" , "Small umberella for sun" , "mushroom" , "Light umbrella to ward off the sun" .)