• synonyms


[sahy-muhl-tey-nee-uhs, sim-uhl-]
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  1. existing, occurring, or operating at the same time; concurrent: simultaneous movements; simultaneous translation.
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Origin of simultaneous

1650–60; < Latin simul together (see similar) + (instan)taneous
Related formssi·mul·ta·ne·ous·ly, adverbsi·mul·ta·ne·ous·ness, si·mul·ta·ne·i·ty [sahy-muhl-tuh-nee-i-tee, sim-uhl-] /ˌsaɪ məl təˈni ɪ ti, ˌsɪm əl-/, nounnon·si·mul·ta·ne·ous, adjectivenon·si·mul·ta·ne·ous·ly, adverbun·si·mul·ta·ne·ous, adjectiveun·si·mul·ta·ne·ous·ly, adverbun·si·mul·ta·ne·ous·ness, noun


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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for simultaneously

Contemporary Examples

Historical Examples

  • We both did this simultaneously, and simultaneously exclaimed "Hullo!"

    It Happened in Egypt

    C. N. Williamson

  • Simultaneously he received a vivid mental photograph of the locality.

    The Black Bag

    Louis Joseph Vance

  • Yet simultaneously he derided himself for the inertness of his imagination.

    Casanova's Homecoming

    Arthur Schnitzler

  • This request from both, simultaneously arranging their mustachios.

    Vivian Grey

    Earl of Beaconsfield, Benjamin Disraeli

  • A piece of good news had simultaneously cured all these gentlemen.

British Dictionary definitions for simultaneously


  1. occurring, existing, or operating at the same time; concurrent
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  1. chess a display in which one player plays a number of opponents at once, walking from board to boardSometimes shortened to: simul
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Derived Formssimultaneously, adverbsimultaneousness or simultaneity (ˌsɪməltəˈniːɪtɪ, US ˌsaɪməltəˈniːɪtɪ), noun

Word Origin

C17: formed on the model of instantaneous from Latin simul at the same time, together
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 simultaneously



1650s, from Medieval Latin simultaneus, perhaps from simultim "at the same time," extended from Latin simul "at the same time" (see similar (adj.)), or from simul with ending abstracted from Late Latin spontaneus, where the -t- is organic. Related: Simultaneously.

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Online Etymology Dictionary, © 2010 Douglas Harper