the GNU version of the Collaborative International Dictionary of English
adj. Existing, happening, or done, at the same time.
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.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. occurring or operating at the same time
Word Usage
"I repeat that we were incapable of waging what we called the simultaneous battle."