What does chassis mean?
A chassis is the base framework of a vehicle — the structural skeleton to which the wheels, engine, axles, and body are attached. In modern automotive use it often refers collectively to the car's underpinnings, distinct from its bodywork or styling. The term has broadened beyond motoring: in electronics and computing, a chassis is the metal housing that holds components such as circuit boards and power supplies, and figuratively it can denote the essential framework of any system or institution. Borrowed from French, where it derives ultimately from Latin 'capsa' (a box), it entered English around the seventeenth century but became widespread only with the rise of the automobile. A notable quirk is that the plural is identical to the singular — one chassis, several chassis — reflecting its French origins and catching out writers who assume an '-es' ending.
The base frame of a motor vehicle, aircraft, or other wheeled machine, on which the body and mechanical components are mounted.
"The racing team stripped the car down to its bare chassis before rebuilding it."
Invariable in the plural: 'several chassis', never 'chassises'.
The main structural housing or framework of an electronic device or piece of equipment, especially a computer case.
"The server's chassis was designed for efficient airflow across multiple hard drives."
The plural is identical to the singular, following French convention. Never write 'chassises'; context or a determiner such as 'two' or 'many' signals plurality.
"The factory produced three hundred chassis last month."
Despite looking like a plural, 'chassis' is singular — and its plural is spelled exactly the same way.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of chassis
Chassis entered English from French in the early seventeenth century, originally meaning the frame of a window or other structure. It derives from Old French 'chas', the root of which traces back through Vulgar Latin 'capsum' to Latin 'capere' (to take or hold), related to 'capsa' meaning a box or container. The automotive sense became dominant from the late nineteenth century as motor vehicles were developed. Cognates include the English word 'chaise' (from the same French root) and 'chase' (both the verb meaning to pursue and the noun for an engraving or a groove), all descending from Latin 'captiare' or related forms.
Related word forms
How chassis is actually used
The plural is identical in form to the singular: one chassis, two chassis. The word carries a technical register, common in automotive, engineering, and computing contexts. In British English the first vowel may be pronounced /æ/, while some speakers use /ɑː/. The pronunciation with an initial /ʃ/ sound reflects the French origin more closely than the anglicised /tʃ/.
Easily confused with chassis
'Chasse' is a ballet step (a gliding movement) borrowed from French meaning 'to chase', whereas 'chassis' is the frame of a vehicle.
'Chassee' is a rare variant spelling of the ballet step 'chassé', not a variant of 'chassis'.