chassis /ˈt͡ʃæ.si/ noun4 •The base frame of a vehicle, such as a motor vehicle.The door being open, Stranleigh walked in unannounced. A two-seated runabout[…]stood by the window, where it could be viewed by passers-by. Further down the room rested a chassis, … — 1913 •A frame or housing containing electrical or mechanical equipment, such as on a computer. •A base frame, or movable railway, along which the carriage of a mounted gun moves backward and forward. •(slang) A woman's buttocks.