Definition of clearances:
(n) :
(retail) A sale of merchandise, especially at significantly reduced prices, usually in order to make room for new merchandise or updated versions of the same merchandise; sometimes as a closeout.
(n) :
The act of clearing or something (such as a space) cleared.
(n) :
The distance between two moving objects, especially between parts of a machine
(n) :
The height or width of a tunnel, bridge or other passage, or the distance between a vehicle and the walls or roof of such passage; a gap, headroom.
(n) :
A permission for a vehicle to proceed, or for a person to travel.
(n) :
A permission to have access to sensitive or secret documents or other information.