SOP:Standard operating procedure
From RTRWIKI
The term standard operating procedure, or SOP, is used in a variety of different contexts, such as healthcare, aviation, education, industry or the military.
The U.S. military uses the term Standing — rather than Standard — Operating Procedure, because a military SOP refers to a unit's unique procedures, which are not standard to another unit. "Standard" would imply that the operating procedure is the only correct one across all units.