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Synonyms

simultaneous

American  
[sahy-muhl-tey-nee-uhs, sim-uhl-] / ˌsaɪ məlˈteɪ ni əs, ˌsɪm əl- /

adjective

  1. existing, occurring, or operating at the same time; concurrent: simultaneous translation.

    simultaneous movements;

    simultaneous translation.

    Synonyms:
    coincident, synchronous

simultaneous British  
/ ˌsaɪməltəˈniːɪtɪ, ˌsɪməltəˈniːɪtɪ, ˌsaɪməlˈteɪnɪəs, ˌsɪməlˈteɪnɪəs /

adjective

  1. occurring, existing, or operating at the same time; concurrent

"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

noun

  1. Sometimes shortened to: simulchess a display in which one player plays a number of opponents at once, walking from board to board

"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

Other Word Forms

  • nonsimultaneous adjective
  • simultaneity noun
  • simultaneously adverb
  • simultaneousness noun
  • unsimultaneous adjective
  • unsimultaneousness noun

Etymology

Origin of simultaneous

First recorded in 1650–60; from Latin simul “together” ( similar ) + (instan)taneous

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.

Put spreads involve the simultaneous purchase and sale of put options with the same expiry but different strike prices.

From MarketWatch • Apr. 1, 2026

A rise in the Treasury General Account mirrors a simultaneous decline in the total stock of bank reserves as payments flow from taxpayers’ bank accounts to the Treasury.

From The Wall Street Journal • Mar. 31, 2026

It felt the way I imagine those famous ’70s consciousness-raising sessions must have felt: like simultaneous creation and discovery.

From Slate • Mar. 31, 2026

They showed that a single incoming stream of ions could be divided into multiple parallel streams for simultaneous analysis.

From Science Daily • Mar. 25, 2026

“We are making arrangements for a series of simultaneous exhibitions and matches for early next year. We are also considering an exhibition match where Bobby would play the entire Dutch Olympic team simultaneously.”

From "Endgame" by Frank Brady