What does simultaneous mean?
Simultaneous means happening, existing, or being done at the same time. It is especially useful when describing two or more events, actions, or activities that unfold in parallel: simultaneous negotiations, simultaneous translation, or simultaneous broadcasts. The word can describe events occurring at the same moment, as well as arrangements that allow several people to participate at once. It is common in formal writing, including journalism, academic research, law, business, and technology, although the simpler phrase “at the same time” is often more suitable in everyday conversation. Simultaneous is related to concurrent, but it generally places stronger emphasis on exact timing or parallel activity. It differs from contemporaneous, which more often means existing during the same general period rather than occurring at precisely the same moment.
adjectiveExisting, happening, or occurring at the same time. It can also mean involving two or more people or things doing something at the same time.
- Happening, existing, or occurring at the same time.
- Involving two or more people or things performing an activity at the same time.
- Achieved or experienced in two or more places or channels at the same time.
"The two teams were presented with simultaneous challenges during the competition."
"The museum offers simultaneous interpretation in several languages."
"The announcement was made through simultaneous radio and online broadcasts."
The word simultaneous comes from the Latin simul, meaning “at the same time,” and is built for ideas that unfold side by side.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does simultaneous come from?
The adjective comes from Latin simultaneus, meaning “at the same time” or “done together,” formed from simul, “at once,” together with a suffix indicating simultaneity. English borrowed the word in the 17th century, initially in contexts involving events or actions occurring together. Related English words include simulate, derived from the same broad Latin root concerned with likeness or appearance, and simultaneity, which developed later as the abstract noun.
Related word forms
How simultaneous is actually used
The word is formal and common in academic, technical, legal, and news contexts. “Concurrent” is often a suitable alternative, while “contemporaneous” tends to refer more broadly to the same period.
Easily confused with simultaneous
Contemporaneous usually describes things existing or occurring in the same general period, whereas simultaneous more specifically emphasizes that events happen at the same time.
Concurrent is closely related and can describe events happening at the same time, but it often emphasizes a shared period, activity, or development rather than precise simultaneity.