Firm order - greet procession (7)
I believe the answer is:
cortege
'procession' is the definition.
(I know that cortege is a type of procession)
'firm order greet' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'order' indicates an anagram.
'greet' anagrammed gives 'rtege'.
'co'+'rtege'='CORTEGE'
(Other definitions for cortege that I've seen before include "Processing figures" , "Entourage, retinue" , "Solemn funeral procession" , "train" .)