Order one sent out for military supplies (8)
I believe the answer is:
ordnance
'military supplies' is the definition.
(I've seen this before)
'order one sent out' is the wordplay.
I cannot really understand how this works, but
'order' could be 'o' (abbreviation e.g. in British honours OM, OBE etc.) and 'o' is present in the answer.
'one' could be 'an' (an apple is one apple) and 'an' is found in the answer.
This explanation may well be incorrect...
'for' acts as a link.
Can you help me to learn more?
(Other definitions for ordnance that I've seen before include "Cannon; munitions" , "type of armament" , "The Survey provides maps" , "Arsenal's big guns" , "Survey may follow this" .)