同(どう)〜

どう

prefix

same; similar; said

formal

1. same; identical

Prefix indicating sameness or identity.

同僚(どうりょう)と昼食(ちゅうしょく)を食(た)べた。

I had lunch with a colleague.

同(どう) + 僚(りょう) = colleague (same work)

同時(どうじ)に二(ふた)つのことはできない。

I can't do two things at the same time.

同(どう) + 時(じ) = same time

同年代(どうねんだい)の友人(ゆうじん)が多(おお)い。

I have many friends of the same generation.

2. the said; the aforementioned

Used in formal writing to refer back to something mentioned.

同社(どうしゃ)は来年(らいねん)新製品(しんせいひん)を発売(はつばい)する。

The said company will release a new product next year.

同(どう) + 社(しゃ) = the same/said company

同氏(どうし)は明日(あした)来日(らいにち)する予定(よてい)だ。

The said person is scheduled to arrive in Japan tomorrow.

同市(どうし)では新(あたら)しい条例(じょうれい)が施行(しこう)された。

A new ordinance was enacted in the said city.

同(どう)〜 is a prefix meaning 'same' or 'the said.'

Common compounds (SAME)

同時(どうじ) (same time; simultaneous)
同僚(どうりょう) (colleague)
同級生(どうきゅうせい) (classmate)
同窓会(どうそうかい) (class reunion; alumni association)
同意(どうい) (agreement; consent)
同様(どうよう) (same; similar)
同居(どうきょ) (living together)
同情(どうじょう) (sympathy)

FORMAL/WRITTEN use (THE SAID)

同社(どうしゃ) (the said company)
同氏(どうし) (the said person)
同日(どうじつ) (the same day; that day)

This usage appears frequently in news articles and formal writing.

Related Words

Related: 同(おな)じ (same (adjective))

general

Added 2026.1.13 16:20 · Revised 2026.9.2 13:01

03500/03962_dou