North, south, east, west; used for giving directions and information from the ground or air in describing the fire (e.g., the west flank or east flank, not right flank or left flank). 

Collective term for the four primary directions: North, South, East, West.

as they appear on the compass, the four primary geographical directions (North, South, East and West)

are directions which involve the main compass routes i.e. North, East, South and West. Giving or receiving directions which for example tell you to head south and to turn north at the main intersectio [..]