undercarriage

under- +‎ carriage

• (General American) IPA^(key): /ˈʌndɚˌkɛɹɪd͡ʒ/
• (Received Pronunciation) IPA^(key): /ˈʌndəˌkæɹɪd͡ʒ/
• Hyphenation: un‧der‧car‧riage

undercarriage (plural undercarriages)

1. The supporting structural framework of a vehicle.
   • 1960 December, “The riding of B.R. coaches”, in Trains Illustrated, page 706:

     The solution to coach riding defects, at least, seems to require much more co-operative practical experiment by all engineering departments to achieve better sympathy between the vehicle body, its undercarriage and the track on which it rides.

2. The landing gear of an aircraft.
3. (euphemistic) The genitalia.