一斉に

• Reading: いっせいに
• Romaji: issei ni
• Kanji breakdown: 一 (ichi/is) — one; 斉 (sei) — even, equal, together
• Pronunciation: /is.seː.ni/

Meaning

Simultaneously; all at once; in unison. The adverbial form emphasising synchronised action.

The adverbial form of 一斉, specifically marking the manner in which multiple agents act at the same time. Extremely common in both written and spoken Japanese. Typical collocations include 一斉に始まる (to begin simultaneously), 一斉に振り向く (to turn around in unison), and 一斉に拍手する (to applaud together).

Examples

1. 先生の合図で生徒たちが一斉に走り出した。 At the teacher's signal, the students all started running at once.
2. 観客が一斉に拍手を送った。 The audience applauded in unison.
3. 朝九時に全国の店舗が一斉にオープンした。 At nine in the morning, stores across the country all opened simultaneously.

Usage Guide

Context: group actions, events, sports, ceremonies

Tone: dynamic

Origin & History

From 一斉 (issei, simultaneous) + に (ni, adverbial particle). The に converts the noun into an adverb modifying the verb, specifying the manner of simultaneous action.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal