Meaning of “clearance” - Learner’s Dictionary

clearance

noun [ C, U ] uk us /ˈklɪərəns/
PERMISSION

permission from someone in authority:

The company needs to get government clearance for the deal.
DISTANCE

the distance that is needed for one thing to avoid touching another thing

REMOVING THINGS

the activity of removing waste or things you do not want from a place:

Demolition and clearance of the site will take two weeks.

(Definition of “clearance” from the Cambridge Learner’s Dictionary © Cambridge University Press)