A chassis (pron.: // or //; plural: "chassis") consists of an internal framework that supports a man-made object in its construction and use. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame (on which the body is mounted) with the wheels and machinery.
Examples of use 
A body (sometimes referred to as "coachwork"), which is usually not necessary for integrity of the structure, is built on the chassis to complete the vehicle.
For commercial vehicles a rolling chassis consists of an assembly of all the essential parts of a truck (without the body) to be ready for operation on the road. The design of a pleasure car chassis will be different than one for commercial vehicles because of the heavier loads and constant work use. Commercial vehicle manufacturers sell “chassis only”, “cowl and chassis”, as well as "chassis cab" versions that can be outfitted with specialized bodies. These include motor homes, fire engines, ambulances, box trucks, etc.
In particular applications, such as school buses, a government agency like National Highway Traffic Safety Administration (NHTSA) in the U.S. defines the design standards of chassis and body conversions.
An armoured fighting vehicle's hull serves as the chassis and comprises the bottom part of the AFV that includes the tracks, engine, driver's seat, and crew compartment. This describes the lower hull, although common usage of might include the upper hull to mean the AFV without the turret. The hull serves as a basis for platforms on tanks, armoured personnel carriers, combat engineering vehicles, etc.
In the absence of a metal frame the chassis refers to the circuit boards and components themselves, not the physical structure.
In computers, the chassis refers to the rigid framework on to which the motherboard, memory, disk drives, and other equipment are mounted. It also supports the shell-like case: the housing that protects all the vital internal equipment from dust, moisture, and tampering. The term "case modding" refers to the artistic styling of otherwise rather functional and plain computer encasings.
See also 
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- Frame (vehicle)
- Backbone chassis
- Monocoque, structural shell, instead of a structural frame
- Starry, Donn A. GEN. Mounted Combat in Vietnam. Vietnam Studies; Department of the Army, Washington, D.C. 1978.
- Association of Licensed Automobile Manufacturers (U.S.) (1922). Official Handbook of Automobiles. National Automobile Association. p. 180. OCLC 6360726. Retrieved 10 September 2010.
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- Grenzeback, Lance R.; Lin, Sandi; Meunier, Jacob (2005). Operational Differences and Similarities among the Motorcoach, School Bus, and Trucking Industries. Transportation Research Board. p. 13. ISBN 978-0-309-08821-3. Retrieved 10 September 2010.
- Starry p. 45, 79, 129, 143, 153, etc.
- Khandpur, Raghbir Singh (2006). Troubleshooting Electronic Equipment. McGraw-Hill Professional. p. 45. ISBN 978-0-07-147731-4. Retrieved 10 September 2010.