• synonyms


[on-too, awn-; unstressed on-tuh, awn-]
See more synonyms for onto on Thesaurus.com
  1. to a place or position on; upon; on: to get onto a horse.
  2. Informal. in or into a state of awareness about: I'm onto your scheme.
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  1. Also surjective. Mathematics. pertaining to a function or map from one set to another set, the range of which is the entire second set.
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Origin of onto

First recorded in 1575–85; on + to
Can be confusedon onto on to


  1. a combining form meaning “being,” used in the formation of compound words: ontogeny.
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Also especially before a vowel, ont-.

Origin of onto-

< New Latin < Greek ont- (stem of ón, neuter present participle of eînai to be) + -o- -o-
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words

adjacent, against, toward, above, on, over

Examples from the Web for onto

Contemporary Examples

Historical Examples

  • He tossed them onto the table, and Hal Dozier rolled his smoke in silence.

  • If you'd been onto your job, things would have been smooth as silk.

  • But it must be something new, or we should have got onto it.

    It Happened in Egypt

    C. N. Williamson

  • With a word of farewell, he climbed out of the cockpit and onto a wing.

    The Solar Magnet

    Sterner St. Paul Meek

  • I can mention his name now without Ketury's landin' onto me like a snowslide.

    Cy Whittaker's Place

    Joseph C. Lincoln

British Dictionary definitions for onto


on to

  1. to a position that is onstep onto the train as it passes
  2. having become aware of (something illicit or secret)the police are onto us
  3. into contact withget onto the factory
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Onto is now generally accepted as a word in its own right. On to is still used, however, where on is considered to be part of the verb: he moved on to a different town as contrasted with he jumped onto the stage


combining form
  1. existence or beingontogeny; ontology
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Word Origin

from Late Greek, from ōn (stem ont-) being, present participle of einai to be
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

Word Origin and History for onto


1580s, as on to, from on + to. Appeared much later than parallel into. As a closed compound (on analogy of into), first recorded 1715.

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word-forming element meaning "a being, individual; being, existence," from Greek onto-, from stem of on (genitive ontos) "being," neuter present participle of einai "to be" (see essence).

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Online Etymology Dictionary, © 2010 Douglas Harper

onto in Medicine


  1. Organism; being:ontogeny.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.