1. official permission or authorization to proceed
2. the removal of unwanted items or people from an area
3. the space between two objects or surfaces

Examples

• The pilot received clearances from air traffic control before takeoff.
• Security clearances are required for classified government work.
• The city ordered clearances of homeless encampments from the park.
• Forest clearances have reduced wildlife habitats significantly.
• Check the clearances between moving parts in the engine.
• The bridge has adequate clearances for tall trucks to pass underneath.
• The store is having clearances on winter clothing this week.
• Warehouse clearances offer great deals on discontinued items.