At once
At once adverb - Without delay or hesitation; with no time intervening.
Simultaneously is a synonym for at once in together topic. In some cases you can use "Simultaneously" instead an adverb phrase "At once", when it comes to topics like at the same time, at one time, at a time. popular alternative
Simultaneously
Simultaneously adverb - At one and the same time.
At once is a synonym for simultaneously in together topic. You can use "At once" instead an adverb "Simultaneously", if it concerns topics such as at the same time, at one time, at a time. popular alternative
Nearby Words: simultaneous, simultaneity
Mutual synonyms
Related pairs
- together and at once
- together and simultaneously
- concurrently and at once
- concurrently and simultaneously
- at the same time and at once
- at the same time and simultaneously
- instantaneously and at once
- instantaneously and simultaneously
- all at once and at once
- all at once and simultaneously
- all together and at once
- all together and simultaneously
- at one time and at once
- at one time and simultaneously
Both terms in one sentence
- One Mexican Standoff between four Mah Jhong players in killer7 winds up with all four men pulling the triggers simultaneously and all dying at once.
Source: Blast Out - In "Little Red Riding Rabbit", The Big Bad Wolf gives Red Riding Hood the bum's rush, while Bugs Bunny simultaneously gives him the bum's rush, throwing both out at once.
Source: Getting the Boot - A common bragging point on the boxes of many games is the number of simultaneously composited scrolling parallax layers the game displays at once.
Source: Motion Parallax
Cite this Source
Simultaneously and At once. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/at_once/simultaneously
At once & Simultaneously. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/at_once/simultaneously>.
Simultaneously or At once. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/at_once/simultaneously.
Google Ngram Viewer shows how "at once" and "simultaneously" have occurred on timeline