from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Happening, existing, or done at the same time. See Synonyms at contemporary.
  • adj. Mathematics Containing variables for which there are values that can satisfy all the equations: simultaneous equations.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Occurring or transpiring at the same time.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Existing, happening, or done, at the same time.

from The Century Dictionary and Cyclopedia

  • Existing, occurring, or operating at the same time; contemporaneous; also, in Aristotelian metaphysics, having the same rank in the order of nature: said of two or more objects, events, ideas, conditions, acts, etc.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. occurring or operating at the same time


from The American Heritage® Dictionary of the English Language, 4th Edition

Latin simul, at the same time; see sem-1 in Indo-European roots + English -taneous (as in instantaneous).

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Medieval Latin simultaneus, from simultim ("at the same time, extended"), from Latin simul ("together, at the same time"); compare similar.


  • I repeat that we were incapable of waging what we called the simultaneous battle.

    The Speech

  • The indictment alleges he also handed over diagrams of the Arlington subway stations and gave suggestions about where to put explosives on trains to kill the most people in simultaneous attacks planned for 2011.

    Farooque Ahmed Arrested For Plotting DC Terrorist Attack

  • Mr. Yoffie: Because we teach the Chinese courses in simultaneous translation, a very large percentage of students is Chinese-speaking with limited English, which leads to certain types of students.

    Harvard a Hit in China, but India Proves Trickier

  • Is there any need to stockpile more than the supplies needed to contain simultaneous outbreaks in several major cities?

    The Volokh Conspiracy » Biological Weapons Amnesia

  • Anyway I'll live but my body said 'stay here under this lovely warm duvet with a cat curled up at your feet and bask' so I've had a glorious snuffly, sneezy morning reading three novels which I have in simultaneous progress.

    Sunday Salon

  • The Eight Pieces for Four Timpani, for example, of which four were performed — "Saeta" and "Canaries" are both early (1949) experiments in simultaneous tempi and metric modulation, and, with their predominantly triplet -, eighth -, and dotted-eighth-note vocabulary, there are fleeting audible glimpses of Reichian phase-shifting.

    Magna Carter (7): Either/Or

  • Fareed Zakaria apparently did not receive the memo inviting him to wet his pants with campus conservatives as they pee in simultaneous fear and anticipation over Ahmedinajad's evil grin.

    Archive 2007-10-01

  • It is supposed to be available in English simultaneous with the Danish edition, published in London and Chicago.

    Kay Nielsen Book Update (again...)

  • But they missed the key difference between Africa and much of the non-tropical world: a large proportion of both the men and women of Africa are involved in simultaneous long term relationships with two or more members of the opposite sex.

    Africa, AIDS, and multiple concurrent relationships

  • Dual protection is defined as the simultaneous prevention of a sexually transmitted infection and unwanted pregnancy.



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