The rear squad ordered to base (12)
I believe the answer is:
headquarters
'base' is the definition.
(I've seen this before)
'the rear squad ordered' is the wordplay.
'ordered' is an anagram indicator.
'the'+'rear'+'squad'='therearsquad'
'therearsquad' is an anagram of 'HEADQUARTERS'.
'to' is the link.
(Other definitions for headquarters that I've seen before include "Base" , "Operational centre" , "Military command post" , "Main office" , "Command centre" .)