1. the landing gear of an aircraft, including wheels, struts, and supporting framework
Usage: aviation
2. the supporting framework beneath a vehicle, especially the chassis and suspension system
Usage: automotive

Examples

• The pilot lowered the undercarriage before landing.
• Ice had formed on the aircraft’s undercarriage during flight.
• The mechanic inspected the car’s undercarriage for rust damage.
• Salt from winter roads can corrode a vehicle’s undercarriage.
• The undercarriage retracted smoothly after takeoff.
• He crawled under the truck to examine its undercarriage.