rotor clearance zone

lateral dual rotor system / side-by-side rotor helicopter

main-rotor head / main-rotor hub

main-rotor hub / main-rotor head

fuselage and landing gear clearance zone

load clearance zone

grid zone / grid-zone

zone standard time (zone time) (ZST)

killing zone / kill zone

grid zone designation / Grid Zone Designator

grey-zone / grey zone (international relations)

hundred-per-cent zone (one-hundred-per-cent zone)

no-fire zone / no fire zone

flight restriction zone / flight restricted zone (FRZ)

air traffic clearance

clearance decontamination

clearance time

debris clearance

diplomatic clearance

percentage clearance

route clearance

clearance of fires

final clearance for the targets

post clearance assessment

post clearance inspection

safe terrain clearance

start-up clearance

take-off clearance

beach clearance unit (BCU )

clearance of overhead crossovers of a bridge

forward side slope ground clearance

axle clearance

bolt-sleeve clearance