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auto

1 American  
[aw-toh] / ˈɔ toʊ /

noun

plural

autos

  1. automobile.

adjective

  1. of or relating to automobiles.

    an auto salesman; auto detailing.
auto- 2 American  

  1. a combining form meaning “self,” “same,” “spontaneous,” used in the formation of compound words.

    autograph, autodidact.
auto- 3 American  

  1. a combining form representing automobile in compound words.

    autocade.
auto- 4 American  

  1. a combining form representing automatic in compound words: autoalarm; autofeed; autofocus . Sometimes also taken as an adjective.

    auto enlarger; auto stop control; auto dialer.
auto. 5 American  

abbreviation

  1. automatic.

  2. automobile.

  3. automotive.

auto 1 British  
/ ˈɔːtəʊ /

noun

    1. short for automobile

    2. ( as modifier )

      auto parts

  2. informal short for autorickshaw

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
auto- 2 British  

combining form

  1. self; same; of or by the same one

    autobiography

  2. acting from or occurring within; self-caused

    autohypnosis

  3. self-propelling; automatic

    automobile
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of auto1

An Americanism dating back to 1895–1900; by shortening

Origin of auto-2

< Greek, combining form of autós self

Origin of auto-3

auto

Explanation

An auto is a car. If you drive your auto too fast, you might get a speeding ticket. The word auto is an informal, shortened form of automobile. You're most likely to hear the word auto when someone's talking about insurance, auto parts, or the auto industry. Automobile was originally a French word, formed from the Greek autos, or "self," and the French mobile, "moving."

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Vocabulary lists containing auto

Scrabble: Four-Letter Words with 3 Vowels

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Volkswagen will stop producing the ID.4 electric crossover at its Tennessee plant in mid-April, a casualty in the U.S. auto industry’s EV retreat.

From The Wall Street Journal • Apr. 9, 2026

Key details: Consumers spent more in February on new cars, clothing and auto insurance and repair.

From MarketWatch • Apr. 9, 2026

Aftermarket auto parts is one business that comes to mind.

From Barron's • Apr. 9, 2026

American car shoppers had cooled on electric vehicles last year after tax credits encouraging their ownership expired in September, and EV sales by big auto makers like Ford Motor and GM fell.

From Barron's • Apr. 8, 2026

She eventually set 17 aviation and auto records.

From "Women in Space" by Karen Bush Gibson

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.