the removal of things that are not wanted
slum clearance (= the removal of houses that are in very bad condition in an area of a town)
a clearance sale (= in a shop/store, when goods are sold cheaply to get rid of them quickly)
the amount of space or distance that is needed between two objects so that they do not touch each other
There is not much clearance for vehicles passing under this bridge.
a clearance of one metre
official permission that is given to sb before they can work somewhere, have particular information, or do sth they want to do
I'm waiting for clearance from headquarters.
All employees at the submarine base require security clearance.
official permission for a person or vehicle to enter or leave an airport or a country
The pilot was waiting for clearance for take-off.
the process of a cheque being paid by a bank
a clearance in football ( soccer ) and some other sports is when a player kicks or hits the ball away from the goal of his or her own team