each person saying; all saying; unanimously; in unison
Describes a situation where many people say the same thing, either together or one after another. Often used with verbs of speaking like 言う, 叫ぶ, 褒める, etc.
みんなが口々に彼の成功を褒めた。
Everyone praised his success, one after another.
The audience called out his name, each in their own voice.
参加者は口々に反対意見を述べた。
The participants voiced their objections, each in turn.
The villagers each voiced their unease.
Non-standard spelling without iteration mark; rarely used.
Reduplication of 口 (mouth) with the adverbial particle に, literally 'mouth by mouth'. The iteration mark 々 indicates repetition of the preceding kanji.