Companion ordering sec to Asia (9)
I believe the answer is:
associate
'companion' is the definition.
('associate' can be a synonym of 'companion')
'ordering sec to asia' is the wordplay.
'ordering' is an anagram indicator.
'sec'+'to'+'asia'='sectoasia'
'sectoasia' with letters rearranged gives 'ASSOCIATE'.
(Other definitions for associate that I've seen before include "Partner, companion" , "Join" , "Partner in work or business" , "Make a connection or affiliate" , "Partner, affiliate" .)