underbody

/ˈʌndərˌbɑdi/
noun
  1. The underside of a vehicle, especially a car or truck.
    • The mechanic inspected the underbody of the car for rust damage.
    • Off-road vehicles have reinforced underbodies to protect against rocks.
    • Salt from winter roads can corrode the underbody of your car.
  2. The lower part of an animal's body.
    • The cat's underbody was soft and white, contrasting with its dark back.
    • The turtle's underbody is called the plastron.
    • Snakes often have a lighter color on their underbody.