Munitions regulation one dropped (8)
I believe the answer is:
ordnance
'munitions' is the definition.
(synonyms)
'regulation one dropped' is the wordplay.
I cannot quite see how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ordnance that I've seen before include "Survey may follow this" , "weapons" , "Anne Cord is in military supplies" , "Mounted guns, cannon" , "guns etc." .)