simultaneously

The cradle-rocking and the song would cease simultaneously for a moment, and an exclamation at highest vocal pitch would take the place of the melody.

1891, Thomas Hardy, Tess of the d'Urbervilles, volume 1, London: James R. Osgood, McIlvaine and Co., page 29

Numa was about to charge—there was little time in which to compare various methods or weigh the probable results of any. And then a number of things happened, almost simultaneously—the lion sprang from his ambush toward the retreating black—Tarzan cried out in warning—and the black turned just in time to see Numa halted in mid-flight by a slender strand of grass rope, the noosed end of which had fallen cleanly about his neck.

1913, Edgar Rice Burroughs, The Return of Tarzan, New York: Ballantine Books, published 1963, page 123

The hens woke up squawking with terror because they had all dreamed simultaneously of hearing a gun go off in the distance.

1943 November – 1944 February (date written; published 1945 August 17), George Orwell [pseudonym; Eric Arthur Blair], Animal Farm […], London: Secker & Warburg, published May 1962, →OCLC

Hidden behind thickets of acronyms and gorse bushes of detail, a new great game is under way across the globe. Some call it geoeconomics, but it's geopolitics too. The current power play consists of an extraordinary range of countries simultaneously sitting down to negotiate big free trade and investment agreements.

2013 July 19, Timothy Garton Ash, “Welcome to the geopolitics of trade, where Dr Pangloss meets Machiavelli”, in The Guardian Weekly, volume 189, number 6, archived from the original on 14 May 2021, page 18