1Doing multiple things together in a single action; all at the same time.
そんなに一度にたくさん質問されても、答えられない。
I can't answer if you ask me so many questions all at once.
洗濯物は一度に洗った方が効率がいい。
It's more efficient to wash the laundry all at once.
会場の電気が一度に消えて、みんな驚いた。
The lights in the venue all went out at once, and everyone was startled.
借金を一度に返すのは難しいので、分割にした。
Since it's hard to pay back the debt all at once, I split it into installments.