一斉

いっせい · issei · JLPT N2 · adverb

all at once

🏁 一斉 = one + in line: everyone moves as one, at the same moment

斉 means even or lined up, as in 斉唱 (singing in unison). Add 一 (one) and the whole line acts as a single unit. 一斉に means all together, and 一斉送信 is one message sent to everyone at once.

一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'

More Japanese words · How Japanese works