At once
At once adverb - Without delay or hesitation; with no time intervening.
In that instant and at once are semantically related. In some cases you can use "In that instant" instead an adverb phrase "At once".
In that instant
At once and in that instant are semantically related. You can use "At once" instead an adverb phrase "In that instant".
Cite this Source
In that instant and At once. (2016). Retrieved 2026, August 03, from https://thesaurus.plus/related/at_once/in_that_instant
At once & In that instant. N.p., 2016. Web. 03 Aug. 2026. <https://thesaurus.plus/related/at_once/in_that_instant>.
In that instant or At once. 2016. Accessed August 03, 2026. https://thesaurus.plus/related/at_once/in_that_instant.
