ferrule /ferˈool, -əl/

1. A metal band, ring or cap on the tip of a stick, etc for reinforcing it
2. A threaded cylindrical fitting for joining two pipes or rods

• air-mechanics
• airmen
• air mile
• air miles
• air-minded
• air miss
• airn
• air-officer
• air-officers
• air-passage
• air-passages
• air-piracies
• air-piracy
• air pistol
• air pistols
• airplane
• airplanes
• air-plant
• air-plants
• air play
• air plays
• air-pocket
• air-pockets
• air pollution
• air pollutions