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simultaneous

[sahy-muh l-tey-nee-uh s, sim-uh l-] /ˌsaɪ məlˈteɪ ni əs, ˌsɪm əl-/
adjective
1.
existing, occurring, or operating at the same time; concurrent:
simultaneous movements; simultaneous translation.
Origin
1650-1660
1650-60; < Latin simul together (see similar) + (instan)taneous
Related forms
simultaneously, adverb
simultaneousness, simultaneity
[sahy-muh l-tuh-nee-i-tee, sim-uh l-] /ˌsaɪ məl təˈni ɪ ti, ˌsɪm əl-/ (Show IPA),
noun
nonsimultaneous, adjective
nonsimultaneously, adverb
unsimultaneous, adjective
unsimultaneously, adverb
unsimultaneousness, noun
Synonyms
synchronous, coincident.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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British Dictionary definitions for simultaneousness

simultaneous

/ˌsɪməlˈteɪnɪəs; US ˌsaɪməlˈteɪnɪəs/
adjective
1.
occurring, existing, or operating at the same time; concurrent
noun
2.
(chess) a display in which one player plays a number of opponents at once, walking from board to board Sometimes shortened to simul
Derived Forms
simultaneously, adverb
simultaneousness, 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
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Word Origin and History for simultaneousness
simultaneous
1650s, from L.L. simultaneus, from L. simul "at the same time" (see similar) + -taneous, abstracted from spontaneous, etc. Related: Simultaneously.
Online Etymology Dictionary, © 2010 Douglas Harper
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