all at once
In one moment
All at once means suddenly or simultaneously.
Something happening all at once occurs without warning: The lights went out all at once.
It also describes multiple things occurring together: Everyone started talking all at once.
The phrase carries a sense of abruptness or convergence—events that might have been gradual or sequential instead collapsing into a single moment.
Unexpectedly, lacking prior notice
- abruptlyWithout gradual transition
- unexpectedlyWithout prior indication
- instantaneouslyOccurring without time passing
- in a flashWithout any delay
out of nowhere · in an instant · precipitously · startlingly · shockingly · jarringly · out of the blue · surprisingly
Occurring together, simultaneously
- togetherIn union or proximity
- in unisonAt the same moment
- concurrentlyAt the same time
- synchronouslyOccurring at identical moments
collectively · jointly · in tandem · as one · in concert · in sync · in parallel · side by side
without warning
Unexpectedly, lacking prior notice
- abruptlyWithout gradual transition
- unexpectedlyWithout prior indication
- instantaneouslyOccurring without time passing
in a flash · out of nowhere · in an instant · precipitously · startlingly · shockingly · jarringly · out of the blue · surprisingly · swiftly
at the same time
Occurring together, simultaneously
- togetherIn union or proximity
- in unisonAt the same moment
- concurrentlyAt the same time
synchronously · collectively · jointly · in tandem · as one · in concert · in sync · in parallel · side by side · en masse
all at oncegradually
In slow stages
bit by bit · little by little · incrementally · step by step · piecemeal
all at onceeventually
At a later time
in due time · in time · sooner or later · later · at last