At once
At once adverb - Without delay or hesitation; with no time intervening.
In a fraction of a second and at once are semantically related. In some cases you can use "In a fraction of a second" instead an adverb phrase "At once".
In a fraction of a second
At once and in a fraction of a second are semantically related. You can use "At once" instead an adverb phrase "In a fraction of a second".
Both terms in one sentence
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At this, he relents, shuts down his suit's weapons... and then targets the hostage-takers, activates a group of smaller shoulder-mounted guns and takes them all out at once with surgical precision in a fraction of a second.
Source: Hostage Situation
Cite this Source
In a fraction of a second and At once. (2016). Retrieved 2026, August 02, from https://thesaurus.plus/related/at_once/in_a_fraction_of_a_second
At once & In a fraction of a second. N.p., 2016. Web. 02 Aug. 2026. <https://thesaurus.plus/related/at_once/in_a_fraction_of_a_second>.
In a fraction of a second or At once. 2016. Accessed August 02, 2026. https://thesaurus.plus/related/at_once/in_a_fraction_of_a_second.
