What does auto mean?
An auto is an automobile — a wheeled motor vehicle used for transporting people. The word arose as a natural shortening of 'automobile', a term built from Greek roots meaning 'self' combined with elements relating to movement, so an auto is literally a self-moving machine. Today 'auto' is most at home in American English, where it appears constantly in journalism, commerce, and everyday speech: one reads about the auto industry, buys auto insurance, or visits an auto show. In British English, 'car' dominates and 'auto' can sound noticeably transatlantic. Beyond the vehicle itself, auto has broadened into a casual shorthand for anything automatic or self-operating, typically appearing before another noun — an auto-reply to an email, an auto-focus lens, an autosave feature. The word carries no strong emotional connotation; its register is informal to neutral, well suited to headlines and conversation but less common in formal writing, where 'automobile' or 'car' would be preferred.
An automobile; a car.
"His first auto was a battered old sedan bought second-hand."
Something automatic or self-operating; used informally before a noun to indicate an automated function.
"I received an auto reply saying she was out of the office."
Standard plural, used when referring to more than one automobile.
"The dealership had dozens of new autos lined up on the lot."
'Auto' is a clipping of 'automobile' — literally 'self-moving' from its Greek roots.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of auto
Auto is a late 19th-century clipping of 'automobile', a word formed from the Greek prefix 'auto-' meaning 'self' and a root relating to movement. The same Greek root appears across English in words such as automatic, autonomous, and autograph. The shortened form spread rapidly in America, where the growing car industry adopted it in phrases like 'auto show' and 'auto parts'.
How auto is actually used
In American English, 'auto' is a common informal or journalistic shorthand for car/automobile, especially in fixed phrases like 'auto industry'. In British English, 'car' is far more common and 'auto' can sound distinctly American. The automatic-mechanism sense normally appears attributively before another noun rather than standing alone.
Easily confused with auto
Auto- with a hyphen is a combining prefix meaning 'self' or 'same' (as in autobiography), whereas 'auto' as a standalone noun is a shortening of automobile.