air lock (n.)

• access
• adit
• approach
• corridor
• entrance
• entranceway
• entry
• entryway
• floodgate
• gangplank
• gangway
• gate
• hall
• in
• ingress
• inlet
• intake
• lock
• opening
• passage
• passageway
• penstock
• sluice
• vestibule
• way
• weir