all at once

• Expression idiomatique signifiant soudainement et de manière inattendue, ou bien en même temps, simultanément.

An idiomatic expression meaning suddenly and unexpectedly, or simultaneously at the same time.

1. SuddenlyB1formal

   Happening without warning; unexpectedly.

   tout à coup

   • All at once, the lights went out.
   • She felt dizzy all at once and had to sit down.
   • All at once, the crowd began to cheer.

2. SimultaneouslyB1formal

   Happening at the same time; all together.

   Tous en même temps

   • The children started talking all at once.
   • Don't try to do everything all at once; take your time.
   • The alarms went off all at once, causing confusion.