同時に|どうじにdoujini[0]heiban (flat)

1. expression, adverbat the same time; at once; simultaneously; concurrently
   二人ふたりの走者そうしゃは同時どうじに決勝けっしょう線せんに着ついた。↗

   The two runners reached the finish line at the same time.
2. expression, conjunctionjust as ...; the moment ...; just after ...as ...と同時に
   駅えきに着つくと同時どうじに彼女かのじょは母ははに電話でんわした。↗

   The moment she arrived at the station, she phoned her mother.
3. expression, conjunction(but) at the same time; as well as; also; on the other hand
   スポーツの逆説ぎゃくせつはスポーツが人ひとを分わけると同時どうじに結むすびつけることだ。↗

   The paradox of sport is that it bonds as it divides.

• Synonym一斉にいっせいにNeutralFor many people or things acting all together, as in 「一斉に走り出す」; stresses moving in unison rather than two things merely overlapping in time.
• Synonym同時どうじNeutralA noun meaning 'the same time', mostly in compounds like 「同時通訳」; it cannot stand alone as an adverb, so it will not replace 「同時に」 in a sentence.
• Synonym一度にいちどにNeutralDoing everything in a single go, as in 「一度に二つ持つ」; the focus is on one occasion or amount, not on two events sharing the same time.
• RelatedともにWrittenWritten/formal prose for 'together, jointly', as in 「家族と共に」; stresses accompanying someone rather than timing.
• RelatedいっぺんにCasualColloquial: getting everything done in one go, as in 「いっぺんに片付ける」; keep it to speech, not formal writing.
• Antonym順次じゅんじNeutralThe antonym: things done one after another in sequence, the opposite of doing them at the same time.

Default: 「同時に」 for two things happening at the same time, or 'just as...'. For a group acting in unison use 「一斉に」; for everything in one go 「一度に」 or colloquial 「一遍に」; 「共に」 is formal prose for 'together with'; 「順次」 is the opposite: one after another.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. それと一緒いっしょに。