clearance

nouns

the distance by which one thing clears another; the space between them
clearance
is derived from
clear
is a type of (narrower)
the distance between things
"fragile items require separation and cushioning"
interval, separation
vertical space available to allow easy passage under something
clearance, headroom, headway
permission to proceed
"the plane was given clearance to land"
clearance
is derived from
clear
is a type of (narrower)
the act of giving a formal (usually written) authorization
license, permission, permit