English Reference
Adverb

simultaneously

adv. time
C1 Advanced Oxford US /ˌsaɪməɫˈteɪniəsɫi/ UK /sˌɪməltˈeɪniəsli/ si·mul·ta·ne·ous·ly

adv.at the exact same time as something else. You use this to describe two or more things happening together.

adv.happening, existing, or done at the exact same time. Often used to describe concurrent processes or events in technical or formal contexts.


SIMPLE

The two runners crossed the finish line simultaneously.

CONTEXTUAL

The software allows multiple users to edit the same document simultaneously from different locations around the world.

COMPLEX

The conductor managed to cue the brass section while simultaneously maintaining a delicate tempo with the strings, demonstrating remarkable coordination and focus.

Usage

Typically placed after the verb or at the end of the clause; can also appear between the auxiliary and main verb.

Pitfall
They arrived simultaneously to the party.They arrived at the party simultaneously.

As a long adverb of time, it usually follows the entire verb phrase rather than interrupting it.

Usage simultaneously address · simultaneously occur · simultaneously present

Zelenskyy called the operation “unique” because it was the first time Ukraine had coordinated 14 types of domestically built aerial and surface drones simultaneously.

Al Jazeera· 14 Aug 2026

In an operation nicknamed the “Big Bang,” the team simultaneously shut down certain power-hungry hardware and switched to lower-power alternatives while keeping the spacecraft warm enough to survive.

ScienceDaily· 10 Aug 2026

Common in science writing


From simultaneous + -ly.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C1 · Advanced
Frequency Common
Updated