Chassis

A chassis is a framework which supports an inanimate object, analogous to an animal's skeleton; eg in an automobile or aeroplane.

A computer's chassis is the rigid framework onto which the motherboard, memory, disk drives[?] and other equipement are mounted. It also supports the shell-like case: the housing that protects all of the vital internal equipment from dust, moisture, and tampering.

External links

http://www.computerhope.com/help/cases.htm