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
Latin simul, at the same time; see sem-1 in Indo-European roots + English -taneous (as in instantaneous).(American Heritage® Dictionary of the English Language, Fourth Edition)
From Medieval Latin simultaneus, from simultim ("at the same time, extended"), from Latin simul ("together, at the same time"); compare similar. (Wiktionary)