A salute keeping soldiers in conformity (9)
I believe the answer is:
agreement
'conformity' is the definition.
(thesaurus)
'a salute keeping soldiers' is the wordplay.
'salute' becomes 'greet' (I've seen this before).
'keeping' means one lot of letters goes inside another.
'soldiers' becomes 'men' (I've seen this before).
'greet' enclosing 'men' is 'greement'.
'a'+'greement'='AGREEMENT'
'in' acts as a link.
(Other definitions for agreement that I've seen before include "Concord, harmony" , "Conformity" , "Accord, contract" , "Correspondence" , "Unlikely result" .)