Soldiers round, left an umbrella (7)
I believe the answer is:
parasol
'an umbrella' is the definition.
(I know that parasol is a type of umbrella)
'soldiers round left' is the wordplay.
'soldiers' becomes 'paras' (para is a kind of soldier).
'round' becomes 'o' (round can mean a round object).
'left' becomes 'l' (common abbreviation).
'paras'+'o'+'l'='PARASOL'
(Other definitions for parasol that I've seen before include "protection from the rays" , "cover" , ""Sunbrella"" , "mushroom" , "Protection from light" .)