WORD ORIGIN a combining form meaning “self,” “same,” “spontaneous,” used in the formation of compound words: autograph, autodidact.
especially before a vowel
Origin of auto- 1
Greek, combining form of autós self a combining form representing automobile in compound words: autocade. a combining form representing automatic in compound words: autoalarm; autofeed; autofocus. Sometimes also taken as an adjective: auto enlarger; auto stop control; auto dialer.
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for auto- auto- sometimes before a vowel aut- combining form self; same; of or by the same one autobiography acting from or occurring within; self-caused autohypnosis self-propelling; automatic automobile Word Origin for auto-
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for auto-
word-forming element meaning "self, one's own, by oneself," from Greek
auto- "self, one's own," combining form of autos "self, same," of unknown origin. Before a vowel, aut-; before an aspirate, auth-. In Greek also used as a prefix to proper names, e.g. automelinna "Melinna herself." The opposite prefix would be allo-.
Online Etymology Dictionary, © 2010 Douglas Harper
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
A prefix meaning oneself, as in autoimmune, producing antibodies or immunity against oneself. It also means by itself, automatic, as in autonomic, governing by itself.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.