simultaneous

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

• (UK) IPA^(key): /ˌsɪm.əlˈteɪ̯.ni.əs/, /ˌsɪm.əlˈteɪ̯.njəs/
• (US) IPA^(key): /ˌsaɪ̯.məlˈteɪ̯.ni.əs/, /ˌsaɪ̯.məlˈteɪ̯.njəs/

  • Audio (US):

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• Rhymes: -eɪniəs, -eɪnɪəs

simultaneous (not comparable)

1. Happening at the same moment.
   • 1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, Chicago, Ill.: Field Museum of Natural History, →ISBN, pages 3-4:

     As with the Lejeuneaceae, this pattern of massive speciation appears to be correlated with the Cretaceous explosion of the angiosperms and the simultaneous creation of a host of new microenvironments, differing in humidity, light intensity, texture, etc.

2. (mathematics, of a set of equations) To be solved for the same values of variables.

• (antonym(s) of “happening at the same moment”): sequential, asynchronous, metachronous