Military missions, for short (3)
I believe the answer is:
ops
'military missions for short' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ops that I've seen before include "Military (or surgical) procedures" , "Military manoeuvres (abbr)" , "Operations (colloq.)" , "Military operations" , "facelifts, perhaps" .)