plural clearances
1
a
: an official decision saying that someone has permission to do something
You'll have to get clearance [=approval] from management to go ahead with the project.
The documents are only available to people with security clearance [=special permission given only to people who are approved to know or see secret things] from the government.
She has a security clearance that allows her to see the classified information.
b
: official permission for an aircraft, pilot, etc., to do something
The pilot got clearance to land.
That flight has not received clearance for landing/takeoff.
a clearance for landing/takeoff
2
: the amount of space between two things
There was only 10 inches of clearance between the car and the side of the tunnel.
The car has a road/ground clearance of seven inches. [=the bottom of the car is seven inches above the road/ground]
a bridge with a 100-foot clearance above the water
3
: the act or process of removing things (such as trees or old buildings) from an area
the clearance of forests for farming
slum clearance to make room for new housing



