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  • auto
    auto
    noun
    automobile.
  • auto-
    auto-
    a combining form meaning “self,” “same,” “spontaneous,” used in the formation of compound words.
  • auto.
    auto.
    abbreviation
    automatic.
Synonyms

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

see origin at 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

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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.

Find insight on MDA Space, Maersk, Grab and more in the latest Market Talks covering the auto and transport sector.

From The Wall Street Journal • May 8, 2026

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Police are asking auto repair shops to contact detectives if anyone recently brought in a sedan matching the description of the suspect’s vehicle.

From Los Angeles Times • May 7, 2026

If you’re designing a chip for an auto, the design process is lengthy.

From Barron's • May 7, 2026

It had auto parts and lumber; shovels, picks, rakes, and seeds for the little gardens the miners scraped into the sides of the mountains.

From "October Sky" by Homer Hickam

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.