auto

UK: /ˈɔːtəʊ/ US: /ˈɔtoʊ/ ,(ô′tō)

Inflections of 'auto' (n): npl: autos

WordReference Random House Learner's Dictionary of American English © 2026

au•to /ˈɔtoʊ/   n. [countable] , pl. -tos. 

1. an automobile.

auto-¹  , prefix. 

1. auto- comes from Greek, where it has the meaning "self.'' This meaning is found in such words as: autocrat, autograph, autonomous, autonomy, autopsy. Also, esp. before a vowel, aut-.

auto-³  ,

WordReference Random House Unabridged Dictionary of American English © 2026

au•to  (ô′tō), n., pl. -tos. 

1. automobile.

• by shortening 1895–1900, American.

auto-¹ ,

1. a combining form meaning "self,'' "same,'' "spontaneous,'' used in the formation of compound words:
   autograph.
   Also,[esp. before a vowel,] aut-. 

• Greek, combining form of autós self 

auto-² ,

1. a combining form representing automobile in compound words:
   autocade.

• see auto

auto-³ ,

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

auto. ,

1. automatic.
2. automobile.
3. automotive.

Collins Concise English Dictionary © HarperCollins Publishers::

auto / ˈɔːtəʊ/ noun ( -tos)

1. short for automobile
2. (as modifier): auto parts

Collins Concise English Dictionary © HarperCollins Publishers::

auto-, (sometimes before a vowel)aut- 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

Etymology: from Greek autos self